


Bifurcation

by FelicityGS



Series: If And Only If [10]
Category: The Avengers (2012)
Genre: Alternate Universe, F/M, M/M, also featuring, baldr, heimdal - Freeform, thanos - Freeform
Language: English
Status: Completed
Published: 2012-09-23
Updated: 2012-12-24
Packaged: 2017-11-14 20:39:26
Rating: Mature
Warnings: No Archive Warnings Apply
Chapters: 17
Words: 25,046
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/519292
Author URL: https://archiveofourown.org/users/FelicityGS/pseuds/FelicityGS
Summary: <blockquote class="userstuff">
              <p>Bifurcation Theory: When a small change is made to a set of values, causing the system to suddenly and rapidly change. Changes often begin to double (bifurcate) until they explode into chaos, losing all prior order.</p>
            </blockquote>





	1. {0, 1, 1,

**Author's Note:**

  * For [aesthesia](https://archiveofourown.org/users/aesthesia/gifts).



> Welcome back. This is the first of the two major long-form fics in the If and Only If series. Stuff is gonna happen dawgs. Update schedule on this is going to be one every two weeks-more if I am able to get chapters to a place I'm happy with. This is slower than my usual, sorry guys-I know how I've spoiled you with everything else being quick. But really, I need to make sure that each chapter links strongly with the rest, and make sure that I've got stuff set up the way I want for the next parts of the series. Quality over quanity.
> 
> Ideally, I'll be able to maintain one chapter every week, but since I don't want to depend on that, we'll say a safe two. If something changes I'll let you know.
> 
> For the maths: bifurcation theory. I'll explain that better later. Hang tight.

**{0, 1, 1,**

Barton is bored.

He prefers being called out to shoot things, finds car chases exciting, and generally thinks that disarming bombs is the most fun a person can have without taking their clothes off. But he's a good agent and goes where he's told and does what he's supposed to.

Does not change that he is _bored_.

He stays up high and watches. One scientist (6', thin as a rail, brown eyes, brown hair—feature after feature marked off and stored with rapid-fire precision) runs a hand through his hair; that will make time 59 this hour. Barton is curious how he still has hair left if this is a usual thing.

That this is the most interesting thing he's had happen is almost enough to drive him to tears.

XXXXXX

It has been nearly two months of this.

It is almost, _almost_ enough to make him miss Budapest.

Today, at least, has unusual readings from the cube. He watches the scientists scurry around like ants or mice or some other animal (Barton is not a poet, he knows this, and he almost pities whoever has been reading his reports about things here because they're suffering right along with him), and flicks his eyes over to the cube. It's pulsing and buzzing.

Fury strolls in and Barton's already zip-lined his way to ground level.

"Where's Barton?!"

"Right here, sir. No one's been in or out, nothing going on at all from this side."

Fury spares him a glance out of his good eye—Barton's sure that he really has both, but he's never really asked either—and looks to the cube. The readings are going nuts. Fury is demanding to know what's happening. Barton can't believe everyone is freaking out as much as they are about this.

After all, it's so obvious.

"Sir."

Fury looks at him.

"It's supposed to be a door."

No comprehension. Right. Barton reminds himself that he's just spent _two months_ with nothing to do but hope for something interesting to happen so maybe he's just faster on the uptake.

"Doors work both ways. _Sir_."

Barton's been working with Fury long enough to catch that slight eye-widen that is tantamount to sudden dawning horror on a normal person. Possibly involving some screaming.

That's when the door opens. Energy lashes out and a portal opens, knocking Barton back against a wall. Mentally, he starts checking through his list of swears because his bow is up in the rafters and all he has is a gun, and he _hates_ guns. He gets back to his feet fast, eyes darting around the room—there's a crouched silhouette on the dais for whenever the cube works.

It worked alright.

Looks human enough as he stands, and also looks like he just crawled out of a fucking pit—when was the last time he'd _eaten_? Dark shadows under brilliant blue eyes, skin stretched tight over sharp cheekbones, black hair, tall (was this guy going to stop standing up _christ_ ) and probably just as sharp and starved as his face underneath all that metal and leather.

No one does anything.

Potential-hostile glances at them, then at the staff-spear- _thing_ he's holding in his hand, like he's surprised that it _actually worked_. Always a great sign.

"Sir, put the staff down slowly."

Potential-hostile blinks at them. Barton really wants to say 'hey, don't fucking spook him because fucking look at the guy, he's _clearly_ not all there,' but he keeps his mouth shut. He hasn't been seen yet, and as he's currently the most skilled agent in the room he'd like to keep it that way. Surprise might be handy to have.

Potential-hostile looks around, sees the cube, and notes the guns. There's the slightest furrow of his brow, then he snarls and energy explodes off the end of the staff into Barton as he goes to take a shot.

Definitely hostile.

The guy is _fast_ , Natasha fast, possibly faster, and in the time it takes Barton twist back to his feet and aim half the room is down. A steely, nothing but skin and bone hand grips around his wrist, twisting so he can't fire, and _fucking seriously_ this is _shameful_ , to be going out like _this_ , not even a single explo—

The hostile pauses and Barton suddenly gets why people say eyes are the windows to the soul.

It's like staring into an abyss with the most slipshod and rickety pathways strung up over it, everything crackling static and noise and _x sub n-plus-loss_

 _Nat_ , he thinks desperately, swallowing and suddenly _afraid_.

"You have heart," the hostile says, sounding shocked, voice as rough and dark and deep as the abyss in his eyes. Apparently the sass filter still isn't off because Barton has time to think _That's the gayest thing I've heard all day_ right before he feels the tip of that _very_ pointy spear press against his breastbone and then:

_Ice blue blue blue ice ice raaagnaaaarok darkness stars abyss x sub n-plus-one equals loss fraaact— things things everywhere digging crawling cackling reaching for him tearing and it's falling falling falling fa—_

_Stop._

_Lines and path and_ order _, everything oh so reasonable, laid out just so and everything's fine as long as he doesn't look down or think about stepping off the edge of pale white-green line beneath his mind's feet_.

Loki is watching him, utterly fascinated.

(Barton has no idea how he knows the hos—no, not hostile, the person? thing's name, but he does. It all seems so _reasonable_. Even if that was the gayest thing he'd heard all day.)

Then Loki turns away and Barton keeps his gun lowered. He's saying something, something about freedom and lies and Barton _knows_ it doesn't matter, not the words Loki's saying, all he hears is what's underneath ( _safety survive safety survive safe safe hide hide hide safe_ ) buzzing in the back of Barton's head like they're his emotions too. He looks and there's Fury—hostile—getting the cube. He doesn't actually need to look to _know_ where Loki is, it's just like Nat, just as instinctive and _comforting_ (briefly, he thinks what the hell and noise-buzzing- _things_ begin to itch at him and he lets the thought go and they let go. Huh). He glances at Loki, knows his mind is drifting—can feel that tug on his own, can feel 'ache' and 'tired' and knows the only thing Loki wants to do is go somewhere safe. Above them, the portal is crackle snapping and collapsing on itself.

"Sir," he says, walking up to Loki, "he's stalling. The building's going to collapse. He means to bury us under a few tons of concrete and steel."

 _Huh_ , _I thought his eyes were blue,_ he thinks as Loki glances at him. Strange—he's never seen a more green green, has no idea how he got it confused.

(What the actual _fuck_ is going on and then crackling cackling _things_ trying to tear and slimy slipping into his head and lets the thought go, focuses on Loki, focuses on pale white-green glow beneath his feet and finds peace again.)

He wants Loki safe, out of here, let's _go_.

He shoots Fury (what the _fuck_ no no no no) in the arm. One of the others grabs the cube in the case—Loki must have been busy, but he can't feel any of them, just Loki Loki lokilokiloki, puts a hand to his god's back as he starts to stumble, supports him one two three steps, because they can't stop, Barton needs to get him somewhere _safe_ that's what Loki wants and right now that's all Barton wants.

To think he'd been bored.


	2. 2,

**Notes for the Chapter:**

> Welcome back. I had a delightfully good week for writing, so this chapter is ready to roll on out. Wish me the best; if I manage to keep hitting my goals for this story early we'll be able to keep the once a week schedule instead of the possible once every two weeks.

**2,**

Tony loves the tower.

Mostly, he loves the view and seeing Chicago lit up at night, loves the way the light glimmers off the windows. He loves that Pepper is never that far away when he's here (like now, the two of them with champagne and celebrating the very first prototype large-scale arc reactor working, nothing but clean energy here).

This is (very nearly) perfect (as close as he's going to get).

"Sir, Agent Coulson is requesting to come in."

"I'm not here," Tony says automatically. SHIELD has left a sour taste in his mouth. Pepper shoots him a Look but he just grins at her, pulls her in close for a kiss. He can feel her smiling against his lips. A kiss that's getting quite interesting and Tony would very much like pursue further—

Coulson walks in.

"How did you get in?" he demands. "Jarvis, how did he get in?"

"Hi, Phil." Pepper, traitor, is smiling at Coulson, stepping away from Tony to shake his hand. "We were just celebrating. Do you want some champagne?"

"His name isn't Phil, it's Agent."

"No, thank you, Ms. Potts." Coulson is all smooth slight smiles, absolutely maddening to read. Tony scowls as Coulson holds out an electronic dossier. Tony should never have invented them for SHIELD to use.

"We went over this. You can't afford me."

"The circumstances are different now," Coulson says, maddening slight smile still on his face. Like he _knows_ Tony won't refuse to help.

Pepper hands Tony her glass; he takes it automatically. Then she takes the dossier from Coulson, takes Tony's glass away, hands him the dossier, and takes her own glass back.

"Is this about the Avengers?" Pepper asks while Tony glares at Coulson. "Which I know nothing about."

"Which was scrapped," Tony adds. "You know, that thing I didn't qualify for."

"I didn't know that either."

"Apparently I'm volatile, self-obsessed, and don't play well with others."

"That I did know."

Tony pretends not to hear her, taking the dossier to the desk and pulling it open. Traitor, he can't help but think fondly. That's why he loves her. He hears her moving off with Coulson, talking about a cellist in Portland, and trust Pepper to know the details about Coulson's life as not Agent. He files it away while he opens up files in the air around himself.

XXXXXX

Natasha is bored.

This is the part of missions that she has to focus on most because otherwise she'll slip, but the truth of the matter is she prefers the dirty work of slipping in and setting up. This part, where they parade around and act like they know what's what and spill all their dirty secrets and tell her what she wants to know, this is predictable and always goes the same way.

Pretending to be frightened is pretty easy, actually, to the point she just has to sit there and filter and listen.

She starts thinking about where she wants to eat after this. It's Barton's turn to buy and her turn to pick, but she isn't quite sure what she's in the mood for. Maybe honest-to-goodness Chinese in some dive they'll have to search out and then convince the owners 'no we really want the other menu.'

Eating out together after missions is one of her favourite things, though she will never admit that to Barton. She doesn't need to; he knows. Just like she knows it's one of his favourite things though he always complains.

One of the guys is tilting her chair back over the second floor leg; she glances over her shoulder and widens her eyes appropriately. Maybe Ecuadorian. She could go for some llapingachos and she'll never say no to a good deep fried plantain.

She mentally adds the names he's talking about to her list and fakes terror as one of them draws a knife.

A cell phone goes off.

Her target answers it and gets a puzzled look on his face. He hesitates, then hands it to her.

"Hello?" Natasha asks, pinning the phone to her ear, irritated as she hears Hill. "Can this wait? What, you want to pull me out _now_?! You can't. He's in the middle of telling me everything."

The target starts to protest and she shoots him a look, eyebrow raised.

XXXXXX

Okay, Tony will admit this is a pretty crack team.

If they'll be able to work together.

Which he doubts.

But whatever. That's not the interesting bit, now is it? No, he's been saving what exactly makes Fury think they need to have the Avengers even though the project was scrapped, what threat is big and bad enough. He flicks open the file and skims over the words. Tesseract—fuck, he hadn't even known SHIELD had that, _he's_ slipping—and apparently it has been stolen— _double fuck_ , SHIELD's slipping.

He opens the video feed from when it was stolen.

Everything stops.

XXXXXX

"No, it can't wait. We need you back here."

"I'm tied to a chair," Natasha says, though both she and Agent Hill know it won't stop her.

"Agent Barton has been compromised."

Everything stops.

XXXXXX

Seventeen years. Seventeen years yesterday—which is when apparently this _thing_ that looks like Loki showed up and took the tesseract.

Seventeen years and Loki should be _dead_ , and instead Thor is _right_ and there's this man-god-thing who is so clearly _Loki_ , who looks desperate-afraid- _survive_ (Afghanistan and staggering in desert sand), talking about freedom and peace, taking out half a room of some of the most skilled agents in the world in the time it takes most people to draw a single breath.

Tony feels bile rise in the back of his throat as numb shock sets in (because Loki's face should never have the look of someone whose just gone to hell and only just managed to come out the other side)(because seventeen years lost _somewhere_ with a shattered mind)(because Loki is _alive_ despite all searching that suggested otherwise).

XXXXXX

_Agent Barton has been compromised._

Natasha stops thinking about dinner and how easy it is to make these people sing the tune she wants. She stops thinking about anything at all.

 _Barton has been compromised_.

The target and his friends don't run. They never do. They aren't that smart.

 _Clint_.

She moves on instinct, training, and black ice cold _rage_.


	3. 3,

**Notes for the Chapter:**

> Welcome back-have an early post. Woop. As fair warning, no more posting from me till Saturday most likely-I'm a bit wiped out right now and need a little time to recoup. I know. A whole three days. Le gasp. 
> 
> Hopefully that'll get me caught up on things and get me some sleep (can you believe I'm going to sleep right after this? 9pm? Really?)
> 
> Anywaaaaay. Enjoy

**3,**

Everything is different now.

It's all faster and almost like magic. Most days he feels like he doesn't understand anything, like people don't even really speak English anymore. Fury told him that they'd send him where he wants, if he wants to catch up with the few people who are still alive.

Steve doesn't really want to.

He reads over the files—paper, and he knows that's a concession, just like he knows all the rest is, just like how they tried to hide how much everything had changed—but he can't do it. He hates that he's survived, he hates that he lost so many people, he hates how _useless_ he feels most days, how lost and confused. This used to be home and now it's… he's not sure.

He stays with SHIELD.

Most days, Steve goes down to the training room. He doesn't need to stay in shape; it comes pretty naturally with the serum.

He needs to do something though, and this is better than thinking about the past.

Better than thinking about calling Peggy.

Better than crying.

Coulson comes in one afternoon and watches him for a bit. Steve ignores him, at least until the punching bag breaks and spills sand all over the floor. Steve catches the towel Coulson throws him and wipes sweat away.

"I've got something for you to look over." Coulson's voice doesn't allow for questions or 'no's, but Steve has found that doesn't mean he can't say no—he gets a sense that Coulson is partly responsible for him being allowed to take over the training room for as long as he does each day and occasionally there's some awkward hero worship (Steve is fairly certain that Coulson did not mean to say "I watched you sleep" when they first spoke).

"Not sure how much use I'll be." Steve moves to put another punching bag up.

"Sometimes we make our own use."

Coulson's already walking out by the time Steve turns to look. A folder is sitting on bench Coulson had been at, stuffed full of documents. Steve looks at it for a few long minutes.

Punching things is easier than moving on.

He huffs a sigh and picks up the folder and starts to look through it.

XXXXXX

Bruce is not really surprised when he walks into the shack near the edge of town and it turns out there is not actually anyone sick to see to. Just a dull resignation. It's very typically SHIELD, though that in itself is unusual because lately when they need anything they just send Barton.

It does not put him at ease.

"Was there anyone sick?" he asks the red-head who approaches.

"No."

Bruce frowns at her. She looks familiar, in that she looks like someone he's heard about but never seen. She has a gun, he knows she has a gun, and despite her acting he can tell she's nervous.

Also not really surprising. Most people are around him.

At least the ones who know.

He pushes down the faint irritation.

"We need your help."

"No."

"Not _his_. Yours. You know the most about radiation and how to find specific signatures."

Bruce hesitates.

"Barton's been compromised."

 _Oh_.

And that does hit him, somewhere deep, makes him grind his teeth, makes the Other Guy growl, because Barton is good people, Barton is probably one of the only people in SHIELD who Bruce can at least trust isn't just trying to use him. It is Barton who has made it clear to SHIELD that Bruce is better off not in their labs, Barton who pokes and prods and has absolutely no regard for Bruce's temper—Barton who treats Bruce like he's still normal, like he isn't half-monster. He can see her take a step back, see her hand reach for the concealed gun, and forces himself to take a deep breath.

To not take it personal even though it is.

"You're Natasha."

She nods.

"Just as a scientist," he confirms, even though the Other Guy is growling and snarling and wants to _break_ who ever 'compromised' Barton.

"Yes. Just as a scientist."

"Okay. Okay. I'll go."

She nods.

Like he had a choice to begin with.

XXXXXX

Jotunheim is cold and dark, with wind that howls incessantly. It is easy to lose track of time when there is no day, easy to lose track of location he is when the stars are hidden by blizzard.

Thor finds himself back at the caves where this started. There are no Jotun here and the Sword has long since been moved. The caves are a bittersweet relief from the snowstorm outside; walking through them, he can find frozen blood spatter. Things do not often get erased by ice.

Seventeen years.

He is not sure where else to look. Knowing Loki—what Loki _was_ (because if he is honest, he no longer knows Loki as he _is_ , cannot even begin to guess what he will find)(and he _will_ find Loki)—he should look for the Sword again. It was why they came to Jotunheim all those years ago and it is possible that Loki will have remembered it and tried to seek it out without knowing why.

As with how Loki would seek Stark out.

Loki is not in the caves but Thor did not truly expect him to be. In truth, he only came here for a brief respite from the storm out. He begins to prepare himself to go out again when there is the faintest tug in his mind, barely a whisper—

 _Loki_.

It is not truly Loki, not really—Loki has changed too much for Thor to trust the bond they share from childhood, used best for tricks and mischief and sneaking about in the dark of night. He has to have, else why has Loki not used it to call for Thor?

No, this is not that bond, but it is similar, and what Thor has been teaching so no matter the realm his slowly spun network can contact him. He fumbles in trying to figure out where this one is from, suddenly shaken, knees nearly giving out in relief even as his stomach knots in dread at what he will find. His hands shake as he makes himself run through the motions Loki taught him what feels like eons ago, rote memorization saving him even as his head is suddenly too full of thought to really _understand_ what he is doing.

Midgard. This is from Midgard.

Loki is alive.

His brother is _alive_.


	4. 5...}

**Notes for the Chapter:**

> Hello hello! Here out is all escalation and rising intensity; we've met (most) of our players, all the major ones for Bifurcation, and we're ready to rock.
> 
> So let's.
> 
> Thank you to everyone who has read, reviewed, or in some way let me know you're enjoying! It might not look it, but this story is freaking hard to write. :P

**5...}**

"I've contacted Thor, sir."

"Good. He ever tell us long that would take?"

"No, sir."

Fury snorts. Natasha stays still, arms folded. She and Bruce had arrived that morning, Bruce quickly setting up in one of the spare labs. She watches Fury walk around the bridge and keeps her mind perfectly still. Waiting. Deep deep in the corner of her mind, locked away, are emotions and lists of all the ways she will hurt the one who has stolen Barton.

She will be no use to Barton if she cannot focus.

A long time ago, he saved her. She plans to do the same for him.

There is no 'if' in Natasha's world.

XXXXXX

Even this deep inside the hellicarrier Bruce can hear the storm beginning to gather outside. He tries not to take it as an omen—man of science—but he's had a chance to watch the video of Loki's arrival now and look through what other information SHIELD is willing to give him.

This doesn't feel right.

The Other Guy even agrees. (Not frightened, Bruce doesn't think the Other Guy even knows what fear is, but it's a recognition of something _wrong_ , something to perhaps punch first before it gets the upper hand, or potentially (this is the shocking part) leave _alone_ in favour of punching other things.)

Bruce _knows_ what's driving Loki—in the set of his mouth and how he moves even though he's clearly about to collapse. It's in how he fights, fast and hard and dirty until nothing is left that can threaten him. Knows it the same way he knows that he'll never die, not so long as the Other Guy is around and watching.

 _Survive_.

Cornered animals are always dangerous; this one looks rabid.

It makes Bruce uneasy and the Other Guy rumble low in the back of his mind.

XXXXXX

A storm rolls in. Natasha had asked Steve to go outside to wait on Loki's brother to arrive, and Steve only hopes the storm doesn't make it difficult for him.

It's a nasty storm, sky going pitch black and crackling with a ferocity that reminds him a bit of storms from his distant childhood. It's raining cats and dogs; Steve can hardly see a few feet in front of him.

Then he goes blind.

He doesn't actually go blind, but his eyes certainly are still readjusting after the bolt of lightning that struck just a few yards away. He can hear some of the SHIELD agents around him talking and yelling, and all his hair has frizzed up from being so close to where the lightning touched down.

There's a man standing in the blackened spot on the deck. He's huge—dwarfs Steve easily, which is saying something—dressed in blue and silver armour and a blood red cape. Lightning blue eyes meet Steve's and Steve realizes with a jolt that this is apparently the person Natasha wanted him to wait on.

He is mostly certain that travel by thunderstorm isn't normal.

"Thor?" he asks cautiously.

The possibly-man (how did he survive that landing?) smiles and loops the hammer he is holding into his belt. It is a wide smile and it puts Steve at ease some even though it doesn't quite manage to reach Thor's eyes. Steve holds his hand out and Thor shakes it. Static shocks up Steve's arm and he forces a grin instead of a yelp.

"Steve Rogers. Natasha asked me to come meet you and get you up to speed." The storm is already gone except for a few wisps of dark gray cloud and a light drizzle.

"Well met, Steve, son of Rogers. I am not sure what speed it is you wish to get me to, but if it brings me more quickly to my brother I am more than happy to oblige." And _wow_ it's kind of like Shakespeare but not really. It's the first time Steve has felt less like of a walking anachronism than everyone else. Huh.

"It's just a phrase here," he says quickly, "It means that I'm going to tell you what we know and what's going on." He begins to walk back inside and Thor falls in step with him. "We don't actually know where your brother is right now, but he hasn't left Earth yet from what we can tell." Thor's face doesn't exactly fall, but the smile does vanish. "We've got some really smart people looking for him."

Steve keeps talking as they walk down the corridors and Thor listens quietly—surprising considering how big he is. Steve keeps expecting Thor's voice to boom whenever he stops Steve to ask questions, but it doesn't. It's… strange. Everything about Thor is strange though, so he doesn't let it get to him.

Just keeps talking, explaining what they know, and Thor just keeps listening.

XXXXXX

"Look, you actually _find_ him and I might consider coming in. But until you do, Tony Stark—who, I'd like to remind you, you cannot afford—has things to do and people to see." Tony flips the phone shut before Fury can say anything else, stepping out of the glass elevator and breezing past the secretary at the desk. He's through the office door before she's managed to get out of her chair

Tony shuts the door behind himself, twisting the lock closed with a snick.

"You," he says, turning around and pointing, "are going to give me some answers."

Baldr raises one eyebrow, leaning back in his chair and folding his hands over his stomach. He looks entirely at ease that Tony just burst into his office without any sort of warning or appointment. One blue eye watches Tony as he moves forward; the other is sightless white, surrounded in scar tissue (some childhood accident involving a great deal of mistletoe and one extraordinarily enraged Loki), and Tony will absolutely never admit that it creeps him out.

"Really, Stark, if you needed to talk you could have simply called," he says with a slow smirk. "After all, it's the _least_ I could do since you left the weapons industry for greener pastures."

Tony grins wide and sinks down into one of the office chairs, sprawling out. He always forgets how smooth (by which he means 'oiled snake writhing in butter') Baldr is until he actually has to deal with him.

(It reminds him of Loki at parties, just before a prank came to fruition, and that might be some of why he always feels flat-footed around the cousin.)

(The rest is in his one good eye, which looks so dreamy and kind and open, the kind of look that people trust instinctively.)

"That's a good one. You been saving that one for whenever we met next?"

"Hardly." Baldr's smirk is still firmly in place. "Some of us do not need note cards to be witty."

"That was _one time_. And I got rid of them," Tony says, playing up _faux_ hurt.

"And then you admitted you to being Iron Man." Baldr smiles broadly, as if he has just scored a point in a game Tony doesn't even know their playing. Maybe he has.

"I'd hardly say that is a point against me. You're just jealous, it's okay, babe. Everyone wants to be me."

Baldr nods slightly; a stupider person, someone who hasn't dealt with him before, might think that he is conceding.

Tony isn't stupid.

(He still remembers the first time he met Baldr and the three government contracts Baldr all but stole from under his nose, smiling and acting star struck by the Stark name.)

(Tony would like to say it was the last time Baldr fooled him.)

Tony shifts in his chair and rests his ankle against his knee, seeing if he can't out-relax Baldr.

"Well, Stark, as delightful as this is, I do have a meeting in," Baldr flicks a look at his wrist, wearing a silver watch probably worth as much as one of Tony's cars (it is a nice watch, though, Tony will give him that), "roughly twenty minutes and you said that you wanted some answers?" He looks back to Tony, all smiles again.

"You mean a bloodbath," Tony corrects. He's been to meetings with Baldr before; they end in exactly thirty minutes (even when booked for hours); the whole room gets left wondering what the hell has happened and everyone walks out thinking they got the best deal. When, point of fact, it's usually the opposite.

"This is why I like you, Stark. You're so very," a brief, just slightly insulting pause (Tony ignores it), "clever. So what, oh what, do I know that the genius of Stark Industries does not?"

"Loki," Tony says (it _does not_ nearly choke him).

Baldr goes entirely rigid. His smile vanishes, and any honesty in his eyes is crushed under a sudden wave of _something_ beneath the surface. He doesn't look disarmingly half-dreaming any more, actually looks _awake_ and _aware_ and other words beginning in 'a' and Tony is growing increasingly cognizant that everything involving the Borson family is incredibly _not normal_.

Then it's just Baldr again, relaxed into his chair, hands neatly folded on his stomach, even as his one good eye is still glittering dangerously.

"Ah. Yes. _Loki_."

Tony stares at Baldr from behind his sunglasses, noting every twitch and inflection in the man's posture.

"I will admit I had thought you would not come to ask me anything involving him, what with it having been very nearly a year since Thor suggested you might. I will also admit that you have a knack for not doing as people expect." Baldr's smile is tight.

"So that was Thor, you guys are just one great big family of gods out on vacation."

"Some of us."

( _Baldr always dreams_ comes unbidden to Tony's mind.)

"Right. Then, supposing you're telling the truth, and all of you just aren't having a family-wide psychotic episode, what's that mean when you wake?"

"Thor told you this," and _wow_ Baldr is nearly biting the words out.

"You owe me answers. I left the weapons market wide-open for you, remember?" Tony quips (he's never met anyone else so viscerally affected by mere mention of Loki the way Tony is)(and it makes him _wonder_ about the relationship between the two possibly-gods, because this is much more passion than 'you accidentally put me in a coma you ass' should really warrant).

"Indeed," and _there's_ the familiar curl of lip. "Vacation is a very apt word for it. We wake up and remember and then it fades, gone into the ether unless we make an effort to keep it close. And who _would_ , really? A human life is hardly comparable to that of a _god_."

"Lie," Tony says softly.

Baldr quirks an eyebrow.

"It's got to be comparable or you wouldn't keep coming back."

"Perhaps," Baldr cedes. _Actually_ cedes, and Tony wishes he were recording this for posterity.

"So it's like a vacation. Some vacations are pretty memorable." Tony stops looking at Baldr and instead focuses on the view through the window. Loki might remember him.

( _Might_.)

"Some are not."

(" _I do not know how much he remembers or how he remembers it._ ")

"Right, thanks." He stands suddenly and heads for the door.

"Stark."

Tony pauses, hand on the newly unlocked door. He looks over his shoulder at Baldr over the top of his sunglasses. Baldr is staring at Tony's left shoulder and ink tattooed in flesh, long since healed, _itches_ even though it's not visible, _burns_ even though there's layers of cloth between Baldr and the ink.

"If I wanted to know if he's still there, wanted to know if it was a _memorable_ vacation..." Baldr smiles vicious and knowing.

Tony doesn't need him to finish the sentence.


	5. Bifurcation

**Summary for the Chapter:**

> Bifurcation Theory: When a small change is made to a set of values, causing the system to suddenly and rapidly change. Changes often begin to double ( _bifurcate_ ) until they explode into chaos, losing all prior order.

**Chapter 5-Bifurcation**

Working with (for) Loki is hardly boring; even SHIELD had (has) its boring moments between the thrills, but this is never boring, never a moment that doesn't feel _right_. Barton doesn't enjoy directing people, or at least he thought he didn't, but this is different, _way_ different (though he can't quite put his finger on why, something scrambling clawing slinking through his mind when he tries).

Every moment that Barton is directing is a moment that Loki is resting (why the fuck does he care if Loki is—hissing sputtering whispers and the white-green glow gutters like a candle flame—because Loki is _order_ and peace and because Loki _hurts_ how could he not care ( _Jesus_ , he thinks, he likes men sometimes but this ridiculous)).

Loki doesn't have to talk for Barton to know what he wants, and he thinks it's nice there's someone he can read that way, someone who can read _him_ that way too. He didn't even know he _needed_ someone ( _but there is someone already what_ ), but clearly he does. (And this was won without hardship, he hasn't had to spend years working with Loki to know how to move in the same spaces, to know what Loki likes and doesn't like, and that's nice (fuck fu(scrabble of claws in his head)ck fuck))

Maybe it's because they're a lot alike, Loki and Nat, Nat and Loki.

Barton's never been so _comforted_ in his life as he is when he's organizing everyone to make sure what Loki wants is what gets done; especially not when he can glance and find Loki curled (he doesn't have to see to know Loki always sleeps on his side, fetal position, takes up as little space as he can (why the _fuck does he kno_ —gutter flicker stumble—because it's Loki why wouldn't he know that?)) underneath a blanket, exhausted and sleeping and _safe_.

It has to be because they're a lot alike, Loki and Nat, Nat and Loki. Loki wakes rapid fast whenever anyone comes near him, stirs and can hardly rest at all. Nat wakes rapid fast whenever anyone comes near her, stirs and can hardly rest at all. But he (she) doesn't wake when it's Barton, she (he) doesn't stir when it's Barton, falls deeper into sleep when Barton runs hands through his (her) hair, _trusts_ Barton the way Barton trusts her (him) and Barton wonders if Loki dances like Nat dances when no one's watching, if Nat hums to herself like Loki does before he speaks, if Loki likes snow the way Nat likes snow, if Nat likes sunflowers the way Loki likes sunflowers.

He shakes the thoughts away ( _musings_ , and Barton is no poet but something about Loki (Nat) makes him a little more capable with words).

Loki's plan is simple and quiet and runs unerring. There's no need to go anywhere other than here—which is exactly where Loki wishes to be, _safe_ —and the scientists can work on what they need to without worry they'll be spotted or found thanks to the layers of concrete and steel overhead. Barton misses the sky but the plan is sound, exactly the opposite of what SHIELD will be expecting after Loki's entrance, and he'd rather Loki be able to sleep than Loki to be in harm's way where Barton cannot (shoot Loki himse(twisting writhing clawing _things_ and bile vision going distant and dizzy—

"Barton?"

He meets green-grey grey-green cool eyes (Loki (Nat) _Loki_ ) and can breath again, doesn't feel sick any more. Just is irritated because Loki needs to _rest,_ Barton has this shit, nothing to worry about, sir, even if there's nothing to shoot.

He realizes that he's said it out loud—he must have (get out of _my head you—_ twist stutter flicker stop _black_ —sir yes sir, you're beautiful sir, did you know that, and there's the gayest thing he's thought all day, today, that he's thinking every second Loki is looking at him and smiling at him and just _being_ with him)—by the slightest twitch up of Loki's lips, not reaching his eyes.

"Of course. Make sure I am not disturbed, goshawk," and Loki smiles and brushes finger tips along Barton's forearm and everything everything everything is warmth and order and peace and solid white-green glow beneath his feet.

XXXXXX

Even though it is only a sending that walks here once more, the empty numberless silences of the spaces Between still crawls along Loki's sight.

XXXXXX

She does not care for her suitor's toys. They do well enough at their task, She supposes, but they are only good in vast numbers (and vast numbers are infinitely more delicious when they are given in sacrifice). They are a chorus of plain voices that sing praise, beautiful only in aggregate.

She watches quicksilver systems trail in the wake of Loki's sending—how clever he is, how clever he always is, to still instinctively create chaos even as he can no longer grasp it consciously—and watches as he speaks with her suitor's Other. The darling prince has not fulfilled her every wish but she can see _possibility_ in his ever step, can follow slowly pulsing sine waves back, see how they tie into the systems of his realms.

 _Possibility_ writhes and twists the air about him, and all the possibilities make his realms totter and groan under the force of what he is meant to do.

 _Army,_ She whispers to him. _Safety,_ She sighs. She smiles as the two twine in his mind.

Loki is the genius touched soloist that needs nothing and no one to aid him. She sighs in longing and love and lust as the _possibilities_ swirl around him and press against him, making him totter on the knife edge precipice before he _burns everything_.

XXXXXX

Seeing into the spaces Between is difficult. It is outside of the Yggdrasil. Heimdal should not have any ability to see Between at all.

Heimdal has been around for a very long time.

It is not Loki that he sees first—it is Her, watching something intently. He follows Her gaze and catches glimmer of functions that belong purely to Yggdrasil. From there, he only has to focus, to narrow his vision, and there:

Loki is demanding an army.

Heimdal cannot so easily push Loki, cannot influence and whisper of things that will make Loki change his mind—Loki is perhaps the only one impervious to his ability to speak and sway things away from Ragnarok. So he does not; he looks at the thing Loki speaks to, studies and strips it bare. He does not know this creature, spite and hate wrapped in a cloak, but he knows Loki.

Knows Loki well.

Spite and hate are easy to press into threatening.

She realizes that Heimdal has Seen, is Watching, and snarls at his work—Heimdal only smiles, because again chance has swirled and shifted and the mere _possibility_ of averting Ragnarok is returned.

XXXXXX

_You think you know pain? He will make you long for that so sweet as pain._

Square root of negative one divided by zero throbs in his mind and soul. His head snaps back, eyes opening and he shakes, trembling at unquantifiable agony.

They would take what he has lost before he can find it, leave him with this dull throbbing _anguish_ and he sits and trembles and _thinks_.

It is no longer enough to be _here_ , beneath the world—it is not _safe_ —but he does not know enough to do more.

Plans shift, twist, bifurcate.

XXXXXX

Barton keeps an eye on Loki as he works, makes sure things are going smoothly and that no one will bother his god while he does his weird meditation thing (Barton finds it endearing).

He sees the moment that Loki's head snaps to the side, green-grey eyes opening and blazing with barely checked rage.

He hurries over towards him, is taking a step, he _knows_ that look, that's the look right before Nat suddenly does someth—

White-green glow vanishes. Breathe, he can't breathe, slime and slick oil coating him, lungs on fire, crawling scrabbling _things_ over him, trying to tear into his head, tearing at his _flesh_ , _in in let us in_ , flails and doesn't know if he's moving towards the surface or further down, and there's a colour—colours—he's missing _things no no no_

"Goshawk," a voice rasps by his ear, a hand on his arm. "Tell me about her."

Barton stares, gasping, into green-green eyes.

 _Who_ he nearly asks and why is she even important because _holy fuck he nearly drowned_ and he can't see, can still feel things pressing but something fire and ice is touching his arm and it grounds him.

"Tell me about her. She likes snow."

Barton can't remember her name but he remembers snow and sunflowers and humming before speaking and dancing so he talks and talks and talks, until _fucking finally_ white-green glow is back beneath his feet, and everything so much more _complicated_ now, so many things spiraling and twisting, a web where once there was just a single straight line—and what's under his feet ends in a sharp drop. His stomach twists.

He meets green-green eyes.

"Natasha," Loki tells him and Barton crumbles under the weight of what he nearly lost, swept in gratitude for the god before him. Loki looks so _puzzled_ by the tears on Barton's face and Barton makes himself suck it up. He catches a flash of something else (loss and just a rather v—), _envy_ , then gone again.

Loki lets go of Barton and the white-green glow doesn't vanish. He takes an unsteady step forward. Loki sweeps away and Barton follows, tugged in his wake, and in his stomach fear twists like a serpent at the sudden _end_ he can see and has no idea where this path will take him—but he can't leave.

(Because if it happens again Loki will not be there to pull him up, he can see it now, soon his new path is not Loki's path and his _ends_ before he meets his god again and terror gnaws at his bones as he follows, one step in front of the other, because this is what Loki wants and all Barton wants is what Loki wants.)

(all Barton wants is Natasha and sick twisting gnawing things scrabble to find purchase in his head)


	6. Interpolation

**Notes for the Chapter:**

> MATH LESSON. I know we haven't had one of those in forever.
> 
> Interpolation is a method of figuring out and mapping things based off of a set of discrete points. You don't really know what you've got till you map it.
> 
> There may be some parallels to sorting stuff out this chapter.

**Chapter 6 - Interpolation**

"Tony, you need to come in."

"Catch someone yet?"

"No."

"Not interested. Try calling down the street though, they always buy cookies off the girl scouts. I'm sure they'd be able to help you out."

"Dr. Banner and Captain America are here."

"Two out of three—science and childhood heroes. Not bad, Coulson. Need more than that to get me in, though; namely one walking impossibility. You've got my number, give me a call when you find him."

_Click_.

Phil smiles slightly as he puts his phone away. Standing at his desk, he pages through the nearly ancient magazine again (he keeps all of his personal records on Stark on paper, most of them typed on an old battered typewriter from college days, because he knows who built SHIELD's systems even if no one else seems to remember. Phil prefers caution). There's a glossy paparazzi photo of two young men in suits leaned drunkenly against each other, arms around each other's waists, both grinning like they know a secret no one else does.

Add seventeen years and a lifetime of clawing their way out of dark places no one else has survived….

A different man (a man who is not Fury's right-hand) would scoff at the idea. Phil has seen many things, and he has encountered quite a bit working for SHIELD. 'Impossible' is not a word that he allows in his vocabulary.

_Namely one walking impossibility_. Tony's word choice only makes Phil more certain.

Phil closes the magazine and slides it back into the folder.

XXXXXX

"Tell me, goshawk, about Fury's little band of warriors."

Barton hesitates (and hey he can hesitate now when did this happen?), meets Loki's green-green eyes, and starts to talk. Loki listens, stopping him to ask pointed questions that draw things out Barton didn't even know he knew. If he tells Loki enough, maybe the future thread that separates Barton from Loki will change—maybe Loki will go back to his other plan again, so simple and safe and solid beneath his feet, not this wispy white-green glow that divides endlessly.

"Then there's Anthony Stark, Iron Man and CEO of Stark Industries. He can be a loose cannon and a terrible team player, genius and likes to let everyone know about it. Coulson is certain that he'll work with them on a threat, but so far Stark has been a bitc—" Barton breaks off, staring at Loki, something dark twisting warnings in his mind.

(slick oily fog and _light hitting 67 degre—_ )

Loki's eyes shimmer blue, rolling up; he staggers. Barton reaches out to steady him and Loki's eyes slide over him then around the rest of the corridor. Loki's hand grips his wrist, near bone-crushing.

"Frac—" Loki strangles on the word. "What _is it_ , the word, it is there, x sub-n-plus _what_ " twisting blue-white glow still threading the green of his eyes. Barton feels like the ground beneath him is wavering, like he's about to fall through and drown again.

"I don't know," Barton says weakly (he's going to be _sick_ this is worse than _everything_ , worse than the nausea when Nat gets injured and he's not allowed to see her). He doesn't know what to do, so he keeps his hands there, steadying Loki, until Loki straightens and his eyes clear all green-green. Loki looks at Barton in confusion, yanks his hand away, and continues walking.

Barton does not mention Stark again.

Loki does not notice.

XXXXXX

Bruce is looking through the data that SHIELD has given him when Natasha walks in. He glances at her and flashes an insincere smile, turning back to his work—it will take hours to process through all the energy readings and find any that match the tesseract.

He doesn't say anything to her. He doesn't actually know Natasha despite any mention in passing Clint had made and he's really not inclined to talk to her. She's dangerous and he isn't sure if she has the same opinion on how involved SHIELD should be in his life as Clint did. Does.

He takes a breath.

"How long will that take?"

Bruce blinks where he is working, but he doesn't pause and he doesn't look at her.

"A few hours."

Natasha gets up and walks to one of the workstations. Bruce stops and watches her.

"Now?"

He glances at the workstation screen; numbers are dropping rapidly, days turning to an hours, perhaps hour, minutes for some of the calculations. His eyebrows rise a little and he looks back to Natasha, meeting her steel-gray gaze. A shiver threads down his spine.

"Give me an hour." Bruce hesitates, then adds, "You're getting him back."

"Yes."

For the first time in years something a little like peace floods him, a tenseness easing out. He can practically hear the huffed sigh of relief the Other Guy is letting out.

"Thank Stark for that trick. He did it last time he consulted for us." She walks out, then pauses at the door. "If Fury asks, tell him you have no idea what he's talking about. We'll blame this one on Stark."

XXXXXX

"Tony? Shouldn't you be with SHIELD?"

Tony blinks and looks around, eyes landing on Pepper. She smiles at him, his hair sticking up every which way, before coming closer, slipping her arms around his waist and looking at what he's got pulled up. Most of it means nothing to her and she's long with come to terms with the fact most things Tony does will not make sense to her. There's a group of pictures in the corner, though, that looks familiar at a glance.

"They don't need me yet," Tony supplies. "It's exactly like SHIELD, jumping the gun."

Not a lie; if they really did need him, they would have asked for Pepper's help by now. Or Phil would have threatened to taser him. (Honestly, Pepper is occasionally willing to pay Phil good money to taser Tony for no other reason than Tony being, well, _Tony_.)

"So what's all this?" she asks, touching one of the energy readings hanging in the air and moving it to take a closer look. It's beautiful, in it's own way, in a way that she associates all readings with Tony and his science.

Tony blinks, then launches into explaining. Pepper doesn't know half of what he says, and they both know it; Pepper, however, knows that Tony really just wants someone to listen. She could ask questions (Tony has learned how to explain somewhere in all their time together, and doesn't even mind it as much as he used to) but she prefers this, really: being spoken to as if she is equal.

While he talks, she eyes the pictures in the corner. She _knows_ that face, but it has to have been years since she's seen it since she can't seem to recall the name. Tony moves the pictures out of the way (out of sight), and Pepper catches the barest tremble of his fingertips and realizes it was intentional.

She doesn't say anything about it though.

_Loki Borson,_ her mind finally supplies and that explains why Tony still hasn't wrapped an arm around her shoulders, why Tony slipped her grip to make grand gestures as he explains about trying to track the energy signatures of the tesseract using Earth's satellite system ("because there is no way SHIELD's hellicarrier would do this, they won't let me have my fun, Pep"). Pepper just crosses her arms and leans against the work table and watches, tilting her head.

It's still a few months until August 20th—of course Pepper knows that date, and of course she always acts like she hasn't realized Tony will vanish that day, acts like she doesn't know he's in Chicago at a grave for someone long dead. Her eyes slip past and she sees today's date: May 27th.

Ah.

The other side of remembering then.

It's just odd, is all. Tony rarely lets his feelings about Loki bleed into the days surrounding May 25th and August 20th—and Pepper knows that Tony hates and lies and feels guilty he's still so caught on the dead teenager. Two days out of the year when Tony acknowledges that he hasn't really let go, and Pepper will give two days over to Loki since all the rest Tony gives to her (and maybe, if she's had a little too much to drink and Tony has been particularly _Tony_ , she might admit that even those two days seem too many. She read the papers then, too, knows that Loki was barely there for three months, and it's taken her hundreds of times longer before Tony finally let her in. She's not bitter, mostly, just… _tired_. There's more than just Loki that makes her relationship with Tony feel like too much sometimes).

She does not like it when Tony falls outside his patterns (despite what anyone thinks, he has them). There's always a reason. (She is reminded of the Omelet Incident).

When her phone rings, she sees the name on it and frowns.

"Sorry, Tony, I have to take this one." She leans forward and snags a light kiss before she goes.

Usually, Tony will try to deepen it.

(She locks away her worry in the time it takes to answer the phone.)

"Hello, Phil."

"Hello, Ms. Potts," Phil says, ever cheerful. Pepper likes Phil. "I have a few questions for you, if you have the time?"

"Wouldn't have answered my phone for you otherwise," she says with a smile, slipping back into her heels before she heads back out the door. She was only meant to stop in for a few minutes anyway, hadn't been expecting to find Tony still here.

"What can you tell me about Loki Borson?"

"He's dead." The smile slips off her face. "Why?"

"His name came up during a meeting, but I couldn't place it. I thought it prudent to take a look, and the Borsons have always been Stark Industries chief competitor. I wanted your opinion on him."

Pepper lets out a breath she hadn't been aware she was holding and nods for Happy to go ahead and start driving. She hates lying to people for Tony, but she will if it involves someone tearing at things Tony doesn't talk about, even friends like Phil, so she's relieved that he won't pry. She knows they will judge Tony for it, and her for not trying to stop him mourning.

"He's been dead for nearly seventeen years. Baldr runs the company now, you could talk to him. He'll know much more about what you need. He's very polite."

(And maybe it's a little bitter and a lot tired that keeps her from warning Phil what Baldr is really like.)

XXXXXX

Phil hangs up his phone.

"Agent Coulson, I presume?" a man says, one eye silver white, the other the friendliest and dreamiest blue. Phil takes the outstretched hand and shakes it. "Baldr Borson, a pleasure to meet you." He smiles and sets off exactly none of Phil's internal warnings. "I understand you have some questions about my cousins?"


	7. Substitution

**Notes for the Chapter:**

> Double feature this week, then we're going on a two week hiatus while I drink... probably water and wine while I'm on vacation, lounging about, eating.. well, food without gluten (because my host is a celiac), have only my phone for electronics, knit, and otherwise do nothing.
> 
> It's gonna be _great_.
> 
> So next update Friday.
> 
> Math lesson: Substitution is taking one thing and replacing it with another. In general, these things must be equal, otherwise you're just gonna fuck up your work. Some people don't have all their marbles together.

They are waiting.

Thor does not enjoy waiting. He has grown more patient and thorough over the years by necessity; now, with Loki both so close and so very far, the waiting drips by in slow seconds, eats at his bones, makes him wonder if _this_ is what Loki's mind is like when bored.

The waiting would not be half so bad if he could _do_ something, but he has crafted that he is not at all related to his human life of before. Falsity is not his forte, but he is also Loki's brother—he can lie by omission well enough to fool even Loki when Loki is distracted. Here no one thinks to ask about the potential connection. So he stands on the bridge and watches people work, arms crossed, allowing static to spark and short electronics brought near him, and smiles as if he has no idea what is going on or what people are talking about.

It is easier than he wants it to be, the pretending not to know.

(He has only to think about Loki, Loki who he does not know and does know and _seventeen years_ )

"We'll find him."

Thor glances at Steve Rogers, who has joined him, arms also crossed over his chest. Steve meets his gaze briefly, trying to be reassuring.

"Thank you, Steve Rogerson," he offers. "Do you have a brother?"

Something pained flashes in Steve's eyes.

"No. Well, not one by blood. He's dead now though."

"Ah. I am sorry for your loss."

Steve's lips twist into a half-smile.

"Don't worry about it. What's your brother like?"

Thor hesitates, looks away at the bridge through the windows and over the expanse of ocean. Truth: he does not know what Loki is like now.

"Loki is clever," Thor finally says. That, he thinks, will not have changed. "Clever and fire and wit."

And, suddenly, Thor finds he desperately wants to tell _anyone_ what Loki _was_ like, so someone will know besides him, so when they find Loki, whatever Loki has become, they will _see_ what is different. Irrational, Loki would say, but Thor _needs_ to make someone see and love Loki as he does.

Steve has been torn from all he knew and thrust into the strange before. He might, Thor thinks, relate.

He starts to tell Steve stories about Loki, _before_ ice and screaming and sleep.

It helps, a little, with the waiting.

XXXXXX

"Tell me, goshawk, do you trust me?"

"Far as I can throw you and then some."

Barton gets a wicked smile.

"I won't let you fall far, goshawk. Trust me."

"Whatever you say, boss." Like he has a choice.

XXXXXX

Phil stares at Baldr.

Baldr smiles back, serene, still setting off exactly none of his alarms. It makes him glad he has recorded this entire conversation.

His cell phone rings; he answers it.

"We found him. Stuttgart. Steve and Thor are en route."

"Good work," Coulson says, then hangs up the phone to look back at Baldr.

One dreamy blue eye and one sightless white eye are trained on him. Phil stands and shakes Baldr's hand.

"Thank you for your cooperation," he says.

Baldr smiles like a snake.

"The pleasure, Agent, has been all mine."

XXXXXX

Some things do not change; axioms upon which a personality is built and universes turn.

Fact: he causes chaos.

(There is a better word for what he causes, but he cannot grasp it, not quite; it's there, in the box of things he must look through _later_ , but which feels as if someone has recently prodded. Something to do with recursive formulas, he suspects. It does not matter, yet; he must ensure that _no one_ will tamper his ability to search foremost.)

He pauses to peer down at the gathering below, taps his spear turned cane against the railing, then proceeds down the stairs. He does not smile; this is strictly business, strictly furthering of his plans. Strictly getting _noticed_. A… distraction. Yes. The sentence of a word problem which obfuscates.

(Fact: he finds Midgardian suits fit him well and feel familiar, offer swirls of unclear memory (there are exactly 43 people not wearing any underwear this evening)(which is not true and he is not looking. He is not sure where the thought arrived from; he sends it on its way)).

He hefts his cane-spear-staff in his hand as he reaches the bottom of the stairs, then flicks it in an easy parabolic arc to grab the bottom—a guard notices him and begins to move forward.

_It takes fifteen pounds of pressure per square inch to break a neck_ , his mind whispers; there is more than enough in the smooth step forward and swing, the (surprisingly delightful—he tries to discard the emotion, he is here as a _distraction_ , not to enjoy himself—but still it _is_ delightful) sound of metal connecting and crunching through bone. Music squeals to a stop and a low gasp runs throughout the room. Loki ignores it and moves forward, grabs hold of the ( _target_ goshawk's mind whispers) man they need and guides him forward before flipping him neatly onto the (altar, altar, sacrifice, blood, _destroy_ rebirth _yeesssss_ ) display with one hand.

Fact: he instinctively tries to substitute his missing pieces with _similar_ (because it is so much easier to _survive_ when he is (incorrectly) whole)

He tucks the spear-cane-staff beneath his arm and pulls out the device that matches goshawk's. He waits a moment, waits until goshawk is ready, then it whirs to life and he stabs down. _It is only an eye_ , Loki thinks. _Pairs are messy in any case_.

There is screaming.

Loki looks up, glances around, blinks slightly. These petty petty mortals are afraid. Afraid of _him_. This is _familiar_ , he has been the center of things wearing a suit _before_ , causing a scene, _yes_ , this is something missing, something real, something _delightful_ , and it swirls up and slots oh so neatly into himself, a part that was missing returned—center. Origin. He is meant to be _here_ in the middle of all things and their fear, yes….

He quite likes their fear.

Likes how it branches and spreads and slips between them, panic flicking from one to another, an exponential growth that is _almost_ as pretty as something recursive, something lost ( _T_ does not equal this but it is related to it). He cannot stop the smile that twists his lips but he does try to restrain it, because this is meant to be business and he must not forget that everything has purpose. He must follow the plan he has laid out.

He lets go and strolls forward; what harm is there in gathering and pulling a little more fear from these creatures? His suit shimmers and dissipates to armour once more. This is not something recursive, but it is _oh so delightful_ and will do to fill in the other parts of himself he does not know, at least for a little while. Besides, he must distract from goshawk's purpose, must be captured himself to _learn_ more about these variables he does not understand that move into and through his plan (function), variables he would direct towards those that _mean to take what he has lost before he can find it and how_ _dare_ _they_.

_(Raaaaaaagnaaaaaaaroooooook_ his mind whisper-hiss-purrs and he laughs high and wild and _wanting_ )


	8. Recursion

**Notes for the Chapter:**

> (r, g, b) is a way of defining colours. red, green, and blue value.
> 
> Recursion in math is something that defines itself using itself. Xn+1 is literally xn, plus one; it is defined by the previous value.
> 
> Primes can also be defined recursively. For a set of positive integers, you can get this:
> 
> 1\. 1 is not a prime number  
> 2\. Any other positive integer is a prime number _if and only if_ it is not divisible by any prime number smaller than itself.
> 
> Pretty neat.
> 
> The Mandelbrot set that is at the core of 'love' in Fractals is a recursive formula. Recursion is incredibly cool-oh.
> 
> And cyclical.
> 
> See you Oct 10th.

**Chapter 8 - Recursion**

Steve isn't sure what he was expecting when he first sees Loki. From the way Thor spoke about him and the whole seventeen years missing, it certainly wasn't… _this_. Captain America is about to jump out of the back of a plane; Loki is laughing, smiling, and the people on the street are all kneeling terrified. He's being well… he looks like he's being a bully.

Neither Steve nor Captain America like bullies.

Steve sees an older man stand up to talk to Loki and his stomach twists. He might not make it in time…

He sees Loki raise his spear and Captain America jumps.

The magic slams into the shield and dissipates. Stall, Steve thinks—Thor is en route (separate because they don't want to chance transport with any stray electricity in battle). Loki blinks at him curiously. The old man, thankfully, is well and Captain America straightens.

"Ah yes. The man out of time." Steve is hurt by the comment; Captain America has people to save, a purpose and lets the words roll off.

Captain America meets Loki's eyes, eyes bluer than Thor's, blue of the blind and sick.

"The only one out of time is you."

Loki laughs at that, something broken, something storybook evil—Steve wonders; Captain America blocks another blast of magic and hurls the shield at Loki like a discus.

No one ever really expects it that first time. Loki staggers back but recovers fast (that is unchanged from Thor's tales), fast enough to dodge when Captain America closes the distance and throws a punch. Loki punches back ( _hard_ , Thor is wrong about that or perhaps _stronger_ ), trying to create distance to use the spear. Captain America kicks his shield into his hand, deflects the sharp bit, and steps in close again. Ducks beneath the swing (Loki is _graceful_ Steve thinks; Captain America only sees a possible flaw to exploit) and manages to land a hit. This almost feels natural, like sparring or dancing; Loki's hits make him rock back but the Captain can tell that he's pulling his punches and presses hard against his foe's reluctance.

Then there's a dagger from nearly _nowhere_ and he ducks behind the shield; Loki laughs, steps back, and the air crackles with the scent of ozone and ice—

Thunder booms and for a moment Steve and Captain both are left blind. Steve rocks back on his feet.

Thor is standing next to him; Loki is sitting up and smoking slightly in a new crater, armour disappearing in favour of the leather he first appeared in. He's holding his hands up, palms out. Steve relaxes fractionally—more so when he realizes Loki only has eyes for Thor.

The pilot has circled the plane back around. Steve glances up, then back to the two brothers.

"Come on," Steve says. "Let's get him back to base."

Thor nods and moves towards Loki. Steve has no idea what to call the expression on his face and doesn't try. Just one more thing to add to all the ways this feels like it's gone sideways.

XXXXXX

Loki is silent. He does not look to where Steve and Thor stand—or, rather, his gaze moves elsewhere when Thor catches him looking.

"This is not right," he tells Steve quietly, pointlessly since Loki will hear anyway. Thor does not care. This should be joyful and it's not and he is not sure what is going on anymore. Steve glances to Thor from where he is leaned against the doorway to the cockpit so Thor continues. "My brother prefers stealth to show."

"I think he _did_ ," Steve says, not unkindly.

It makes Thor sick (that Loki is so changed, that he has taken _so long_ to find his little brother).

He looks back to Loki, Loki whose eyes are all wrong, Loki who is older and hair unkempt and smile too bitter-jagged and—

"We'll be back soon. You guys can talk then."

Thor nods. He likes Steve; he makes much sense and Thor can relate, a little, to the situation Steve has woken up to. He goes back to looking at his brother, who is watching them, face neutral and head tilted slightly to the side (like when Thor does something sly instead of honourable when fighting).

There is a beep from the cockpit and the pilot is looking down. Loki frowns; Thor tears his gaze away for a moment.

"What is it?" Steve asks.

"Unidentified aircraft, give me—"

The back door of the quinjet tears open, smelling of molten metal, but there's nothing there. Thor grabs for Mjolnir anyway. Something unseen grabs Loki and hauls him to his feet by the throat; Loki claws at… a hand? And then is dragged out and away.

Something inside Thor snaps.

XXXXXX

The (can't really be) Loki is _strong_ , grip denting the metal of Tony's suit.

"The cloaking worked, sir. However, I recommend you hurry; the look on Mr. Borson's face suggests he will be following momentarily."

"Thanks, Jarvis." Spying the cliff side, he crash lands, almost feeling bad about the dazed look in ( _why are you alive, ruining my life_ ) Loki's eyes. Instead, he takes advantage, twists and flips Loki onto his stomach before he can recover, straddles him to pin him down (doesn't _that_ bring back memories), and decloaks.

Thunder is rumbling.

"ETA?"

"Four minutes at current speed. More than enough time for a tryst, considering your positions."

Tony rips the pauldron away, then tears through coat and shirt to the bare skin, to ( _I thought you were_ dead) Loki's shoulder, and Baldr has to be leading him on, has to.

White scars and bruises, flesh smooth and unbroken where _x n+1 = xn2 \+ c_ should be.

Tony laughs, cackles. Oh what a fool. He tears off his left (dented) gauntlet anyway; the not-Loki is staring at him from the corner of his eye, eyes all wrong (really, he should have _known_ from that alone). Reaches with bare fingers to trace the not-there handwriting, his hand-writing, and what was he thi—

Loki (Loki Loki _his_ Loki) _screams_ , pain-despair- _loss_ , bucks and writhes at the touch. White fire blazes up Tony's hand arm burns him heart stutter stutter thuds gasping white heat love is _this_.

Ink bleeds to meet Tony's fingertips, familiar (red) lines and Tony thinks his shoulder arm hand is numb but for the aching bleeding _agony_ of (green) equation on Tony's shoulder like a live thing twisting beneath the flesh.

"Sir, two minutes."

Tony lets go, stumbles to his feet, and falls off the cliff.

XXXXXX

square root of negative one divided by zero, blue-white chains ache crack rattle _it burns_ stop stop stop null _it hurts stop_ get out out end null _stop_ burns _loss is_

xn+1 (fractal) = xn2 (recursion) + c ( _love_ )

 _They are in bed, brown (60, 35, 23) eyes flecked with honey (233, 196, 103) flicking partway open to stare at him. A hand (rough, calloused, last finger exactly three inches long) reaches over and one (1) finger traces over still tender lines number formula (fractals)(I love you infinitely and more completely and complexly than I can ever express) on his left shoulder, over his heart, and his heart_ warms _(positive in place of negative) at that, cannot stop the smile that comes to his lips and he says "X sub n-plus-one equals" and T finishes "x sub n squared plus c"_

and it hurts _oh gods make it STOP_ loss make it stop please please please _**anything**_ it _hurts_ stop stopstop _stooooooooooop_

XXXXXX

Thor finds Loki by the sound of his screams, pleading incoherent screams and when he lands, Mjolnir at ready to strike down who has taken and hurt (is hurting) Loki because _he will not lose him again_.

Only Loki is alone; Thor drops Mjolnir and rushes to Loki, Loki whose armour is torn, whose fingers are scratching at his head, Loki who's curled tight into a ball and does not stop screaming begging pleading one word over and over and over:

_stop_

Thor grabs Loki's (too thin) wrists and pulls his hands away before he can injure himself.

"Loki, brother" and Thor's voice cracks because _this should not have happened_. He looks away, scans the deserted cliff and sees a red-gold gauntlet, dented. Pulls Loki to sitting, looks:

quickly fading red ink twist slipping back beneath the skin--

dream-brand

Loki's head lolls on his shoulder but he is not screaming any longer. Just rapid gasping breath and shudders.

"Brother," Thor whispers, touching Loki's face.

Loki snaps back the rest of the way. His eyes are _green_ but for fine spiderweb strands of twisting sick blue and they narrow as he meets Thor's gaze.

"And what," Loki hisses, "gives you right to call me that?"


	9. Convergence

**Notes for the Chapter:**

> Firstly, this chapter was the hardest one to write thus far.
> 
> Secondly, I know I said no update till the 10th but I changed my mind because omg omg omg Romney didn't get elected so I can chill the fuck out finally yesssss and I want to share my joy, and I thought to myself 'Fel, you know how to spread joy? Give people an early IFF update.'
> 
> So bam.
> 
> Thirdly, after chapter 10, I think all the chapters have names. I've only got another 4 chapters to hammer out and then chapter 17 has been written since I published Origin all that time ago. So. We're nearly nearly done with Bifurcation!
> 
> Anyway, yays all around.

Bruce is looking at some files when he catches sight of movement in his peripheral. He glances up, sees an armed escort. Has to take a few calming breaths because they aren't there for _him_. Once he gets that through to everyone, it gets easier to focus again.

Green eyes webbed in blue meet his own. Bruce blinks and removes his glasses to get a better look. The newly captured god ( _hurt smash_ )(hush)( _smash first_ ) grins wide and gracious at him, turning his head to follow Bruce for a few moments before he's whisked around a corner and out of sight.

Bruce stares out the window, files forgotten on the table for a few moments. In his mind, low buzzing grumble growl—but it's all _wrong._ It feels like he's just brushed up against sandpaper, left his mind raw and blurred. A low pitched whine that won't go away, claws pricking deep in his nerves but not tugging down, not yet. No, but the _threat_ of it was there, buzzing hissing claw-digging—

"Dr. Banner?"

Bruce starts, looks away from the hallway outside to one Captain America dressed in red, white, and blue, face earnest and worried. He's holding a spear carefully, as if afraid it will bite.

Bruce recognizes it from the underground footage and grows a little more uneasy. There's a blue shard nestled between the blades at the top, a sliver of the cube, and it hums with angry energy.

"Miss—Agent Romanoff asked me to bring this to you. She said you should be able to use it to find the tesseract." Steve is still watching him.

( _smash crush destroy noise loud stop white_ )

(hush)

( _low deep growl_ )

"Sure thing," Bruce says, forcing a smile to his lips. "Just set it down here and I'll get to work. Thanks."

Steve sets it down where Bruce points, casts a glance about the room, and leaves.

Bruce looks at the spear and tries to breathe through the sudden sick twisting wrong in the air. Maybe he should take a few minutes to go and meet the rest of the team, catch his breath.

(let anger fade and white noise whine grating on his nerves fade)

XXXXXX

"There is more involved here than simply a Norse myth trying to take over the Earth."

Fury considers Coulson. They have worked together for years now, and while Fury does not trust anyone he does very nearly trust Coulson. The other man is steady, unflappable, quiet and cool where Fury goes in with fury (he hates hearing the jokes about his name, but he's okay if he's the one making them).

They work well together.

"You think the tesseract is secondary." Fury thinks about this. He knew the look in Loki's eyes when he stumbled, has seen it in the eyes of men urged on by a threat to something held dear. Knows that villainy is rarely so black and white as it is painted because SHIELD works in the grey area itself. "Mother _fucker_. Why can't these fucking things pick some other place to do this shit? They get back yet?"

"Captain America reported in; they arrived just a few minutes ago."

Fury eyes Coulson.

"Don't fucking tell him you watched him sleep again."

Coulson's lips twitch slightly.

"Goddammit. I want you with Thor when I interrogate our new psychopath, figure out if the other Borson is telling the truth or not."

Fury turns away and folds his arms, glaring at the skyline and ocean stretched out in all directions.

It's never fucking easy.

XXXXXX

"—my brother is not—"

"Hi, hello, did you miss me? So what are we doing? How is this going to go down? I hear you guys caught him, great job, now let's get him to tell us where our cube is and we're good." Tony waltzes into the room, rakes his eyes over the rest of the bridge, then turns to the circular table where the 'team' is gathered. His eyes land on Bruce and he goes off again, ignoring the thoughtful look Thor is giving him, the disapproval rolling in waves off Steve and Fury. "Dr. Banner, nice to meet you, big fan of your work. How you go all green."

Banner smiles awkwardly, clearly discomfited (good, Tony thinks, he's not the only one totally out of fucking place and Loki is alive and Thor is here—

Right. Thor. Thor who's watching him, three parts confused and one part appraising.

"You must be the big brother, read about you in the files. God, right?" Tony holds his hand out, shake, smile for the crowd—and holy hell, when did Thor learn to lie because Tony is almost convinced he's never met Thor and Tony still remembers last year clear as day (how could he ever forget). Thor's smile reads 'I have no idea what the joke is here but you are amusing enough;' it's the tightness of his grip that gives him away.

_Fuck_.

Tony's spent a lifetime distracting and misdirecting, a lifetime of avoiding conversations that need to happen.

(And there is a conversation there with Thor.)

"Tony—"

"Stark, actually," Tony corrects, spinning on Fury, vicious cold grin in place. "Only my friends get to call me Tony."

"Is everything a joke to you?"

Ah, and Steve, golden boy. Tony has absolutely no time or extra energy to devote to going over the mess that Captain America is, the tangled emotions of father-hero-hatred that circles vicious whenever someone gushes warm praises upon America's brightest hero. Tony decides that he wants a do-over for this month, because that's two people who have entirely altered the course of his life coming back from the grave (and a part of his mind is sick with fear that next is going to be Yinsen or Obi—Obiadiah, and _what the hell._ )

No. Tony is here for one reason, currently walking along the edge of the glass cage deep in the belly of SHIELD. He'll figure Steve out at a later date, provided they don't all get killed in the meantime.

" _Funny_ things are. Lighten the mood." Tony waggles his eyebrows and shoots Steve his best 'have I got a deal for you' smile, usually reserved for the press. He looks away, towards Bruce again. "You know, before we get to stomping people's faces in."

What he is isn't expecting is Steve to keep going.

"This isn't a joke. People have _died_."

"Yeah, that's why they brought me in. The armour, the science, I've got _all_ our bases covered."

Something twinges in Steve's eyes; Tony realizes he's just managed to step right on Steve's gaping raw sore spot. Amateur mistake (this whole situation just has him stumbling every which way (can't get the sight of (red) ink out of his mind's eye)).

"Big man in a suit of armour, take that off and what are you?"

The room is silent, everyone watching quiet. Tony looks back at Steve evenly.

"Genius, billionaire, playboy, philanthropist."

"I know guys with none of that worth ten of you."

This isn't fucking happening. He is not about to get torn down by his childhood superhero for _not being good enough_. He doesn't have time for this.

"The only thing you really fight for is yourself. You're not the guy to make the sacrifice play."

He doesn't look away from Steve, keeps his face still. Part of him, analytical part that pokes and prods and tears, the part that's gotten used to reading a person and responding in just the right way (to piss them off) can see what's going on here, or thinks it does. Tony presses his lips together tightly.

"To lay down on the wire and let the other guy crawl over you."

Tony glances down (not letting this get to me _, not_ , here for one person, Loki and a tattoo brand), swallows and looks back up. Meets Steve's gaze as evenly as he possibly can.

"I think I would just cut the wire."

Bruce snorts a little in amusement to his right, cuts the tension away and Tony can (finally) slip back into the (never-lost) calloused shell he protects himself with.

"Always a way out."

"That's the whole thing about jokes," Tony says, grinning wide and easy and _wanting_.

"Ladies, if you are done _arguing_ like little _bitches_ , you have work to do," Fury interrupts—and why the fuck didn't he interrupt sooner. Tony shoves it back into his little lock box of stuff to deal with later, _later_ (after Loki). "And I have a prisoner to question."

(like he has any idea what he's doing)

XXXXXX

Thor watches.

"It is a very nice cage."

Loki circles a slow spiral on the screen.

(Loki loves spirals.)

(Loved.)

"But not, I think, built for me."

Loki's smile is... _mamba-like_ , Father has said.

"It was built for something much stronger than you."

Loki pauses. (He is near the center of his slow spiral arc, a perfect spiral, a perfect sequence.)

(Loki loved spirals.)

(Loves?)

"Ah, your friendly beast, creature that hides behind illusion and human flesh. How tame is he, I wonder? Tame enough you trust him not bite your own hand?"

Loki would be right to bite his hand, Thor thinks numbly.

Loki smiles, mamba-like.

XXXXXX

He cannot see where white-green glow ends.

And he's not worried, Clint Barton does not worry about plans, just follows order (but if he _falls_ Loki cannot catch him, if he _falls_ then ( _do you trust me, goshawk?_ ) he will lose _him_ (her), Loki's line is somewhere else and it (doesn't) makes Clint sick that his own comes so close before ending in a sudden sharp _drop_ ).

It's like it's his first assignment again. What _is_ this?

He watches the sky outside the cockpit, thumbs along the grip of his bow.

_Soon_ , he thinks.

(Soon.)

( _It will be okay, Lo(Nat)ki._ )

XXXXXX

The thing about spending most of his time in war-torn areas playing physician is that Bruce very rarely meets people who think on the same level he does. He doesn't mind-after all, he's got an internal... 'friend' who has to speak with as slowly and calmly as possible. He is quite okay with explaining things, when people want to learn.

Working with Tony is a sudden reminder of just what he left behind.

Working with Tony is also like some sort of crash course in small annoyances. And Bruce can't tell if Tony is trying to distract him or trying to push him into changing or if it's something else. Maybe a combination. But really, it's a bit like Barton. It's nice being treated like he's not some sort of big mean green rage machine.

(Even if it is a part of him on the inside.)

Any other time, the pokes, prods, and occasional shock would not bother him. But in the lab there is a high-pitched whine. It makes the Other Guy growl and grumble and snarl, sets Bruce's own teeth on edge. Something is going to happen. This is quiet before the storm, that sets dogs barking and cats yowling. And the particular blue light Loki's staff lets off is just the wrong shade that even just running scans on it makes his eyes ache. Like it's blue but also sixteen other colours at once.

(Bruce knows this is impossible.)

(The Other Guy grumbles deep, shifts. _Break. Smash._ )

(Punch him before _everything else_.)

"What do you know about Loki anyway?" Bruce asks, glancing up at Tony.

There is the briefest flash of _something_ on Tony's face and gone so fast Bruce almost thinks he hallucinated it. Something hurt, something lost. The Other Guy stops growling, sudden sharp curiosity spreading in his head, and that high-pitched whine is no longer so loud.

Bruce might not enjoy what he is, but he's learned to trust himself. All of himself.

"Tony," he says slowly, sudden dread certainty in his stomach, "what do you know about Loki?"


	10. Loki (SHIELD(avengers))

**Notes for the Chapter:**

> Welcome back! Saturday is Loki's day; did you know that?
> 
> Anyway. I would like to remind everyone this an AU—alternate universe—and so some of these details and events are going to happen differently than they did in the movie. I'm using the movie as a framework.
> 
> Math pr0n lesson: The chapter title is an inverse function. By inputting a function into its inverse, it will undo what the function did. So, for example, if g is the inverse of f and I put the results f(x) into g, then I'll end up back with what I first put into f. So say x = 2 and f(x) = 6. If you put 6 into g, then you'll get 2.
> 
> We covered inverse functions awhile ago. There may be a theme involving the application of some early story titles in the series; no, you won't necessarily need to grasp the concept to enjoy the chapter, but I do want to cycle through old concepts because _reasons_.
> 
> Ps- this is one of my favourite chapters

She _wants_ to demand, to grip hair in her fist and slam face to glass, to draw out every last drop of information until she has Clint returned to her, safe and whole.

She approaches quietly, keeps her pose hesitant and unsure, and meets shattered green eyes webbed in sick blue.

(She _needs_ to keep calm.)

"You must be Natasha," he says, smiling crookedly, drawing closer to the edge of his cage. His eyes sparkle but there is something else, something _wanting_. "Barton has told me so _much_ about you."

(She slips into old habits, harnesses rage into ice. _Focus_.)

XXXXXX

Tony flashes Bruce a smile.

"Loki, crazy guy downstairs, thinks he's a god?"

Bruce moves to where Tony is working and pushes readings out of the way. He meets brown eyes a bit too hurt and a bit too wanting for someone who fills a room with presence, glib and mocking in equal parts.

"But you know him. Or think you do."

Tony laughs.

"This is important. He took Agent Barton."

(The Other Guy _growls_.)

"Legolas, right, the archer." Tony snaps his fingers, moves away, space so that Bruce can't see his eyes. Bruce settles back and crosses his arms loosely.

"Clint," Bruce says and Tony's face twists into a grimace—guilt and pain and sorrow—then gone again.

XXXXXX

"Love is for children," she tells Loki and she means to finish, means to say more, but Loki wavers, his eyes roll for a moment, mouth going slack as he _searches_ over the word (love) and for the first time in years Natasha Romanova is taken off-guard.

Actually startles when he snarls, a fist slamming into the glass, eyes all brittle rage, a little more blue melted away, a little more poison green swirling _lost_.

"What is _he_?" vicious snarl and Natasha hears _what am_ _ **I**_ _._

"A debt."

" _Tell me_."

XXXXXX

"What is she doing?" Thor demands, seeing Natasha speaking with his brother, voice too soft and quiet to be easily picked up. Loki's stance is all wrong, snake-smile gone. Natasha says something and for a moment Loki wavers, fingertips pressed against glass, before he _snarls_ and his fist slams into the glass.

Thor goes to leave; a SHIELD agent tries to stop him.

"I'd get out of his way," Steve suggests to the agent as Thor scowls, hand edging towards his hammer. Thor gives a swift nod to Steve before hurrying out.

XXXXXX

Tony is nearly dancing about the lab, not able to stand still, and he goes near the spear, runs a scanner along it. Bruce follows him.

"He just looks like someone I used to know. It's stupid."

_Liar_ he thinks. His instincts are screaming, and that awful hum-buzz-noise is back.

Worse, he realizes, the closer Tony is to the spear. Tony moves away and it fades a little again. Like it's straining under weight, ready to break, and Tony is outside force pressing down on it.

"Except it's more than that."

Tony offers Bruce a million-watt grin.

"Nope. You're reading too much into things."

"Except you know Thor, too, when no one else does."

Tony freezes and Bruce _knows_ then, that he's right, that Tony knows Loki, that Tony is here for that, for him, just like Bruce is here for Clint, and he wonders what he's supposed to do with that knowledge.

_Smash him first_ the Other Guy... suggests.

Bruce rubs his temple with one hand, high-pitched whine throbbing as Tony begins to pace.

XXXXXX

Coulson is waiting for Thor as he goes down the hallway, armed with a polite smile.

"Out of my way," Thor snaps because he does not know what Natasha is saying or doing to Loki, and he will not have Loki hurt.

Not more. Not again.

"I'm afraid I can't do that right now, Mr. Borson."

Thor pauses, mind catching the name that no one here should know. His eyes narrow and unbidden the lights around them flicker.

"Move aside," Thor repeats.

XXXXXX

_He knows all this_ , Natasha thinks as she talks, but Loki's eyes are wide, pain and loss and some primal _need_ moving beneath the surface. His face is blank—but that's his tell, goes more blank the more he's off-balance.

"He was sent to kill me. He made a different call," she finishes.

Loki smiles, a beautiful smile, that does nothing to change how blank the rest of his features are.

"And _if_ I were to spare him?"

She _wants_.

"I won't let you out."

His smile only grows wider and she wonders what she missed, because it has to have been something, because this smile is _honest_ , it's the way he smiled at Fury, and the blank is clearing away to something _else_ and when did she get so out of practice, she can't, not now, not so close.

"You are," he purrs, "simply _divine_. I would take this world and you would trade it for one man?"

"Regimes fall every day. I tend not to weep over that, I'm Russian... or I was."

"And now?"

His voice is as _honest_ as his smile, eyes shimmering mad-happy- _wanting_.

Natasha _wants_ , too.

She takes the bait.

"You're making this complicated. It's not. I have red on my ledger. I want it gone." _I want him back_.

Loki's eyes flash and he surprises her again, not triumph or glee or anything to show he's got the upper hand:

_envy-pain-jealousy-_ _**loss** _

"I won't let you _touch him_ ," he snarls, fist slamming against glass again. She takes a step back involuntarily, heart rate speeding up as it hasn't when working, not in years. "Not _you_ , Dreykov's daughter, _Bringer_ , not even this pathetic realm is enough for me to let him into your hands again. I will kill you in every way you fear, slowly, intimately, until there is nothing left, _until he is made safe_. He is _mine_."

She stares wide-eyed because this isn't about Barton, it's about what Barton _means_ , and there's what she's missing.

"You're mad," she whispers.

"Oh, yes," he chuckles, smile all broken edges and poison. "And soon he will be too."

Mad. Insane. A different sort of mad. Anger. The Hulk.

Loki doesn't need her to let him out.

"Loki is planning to unleash the Hulk. Keep Banner in the lab, I'm on my way. Get Thor there, too." She pauses, voice professional through training and not because she is actually calm. He watches her, face blank once more—but it's a ploy. Has to be.

"Thank you for your cooperation."

His eyes are smiling.

XXXXXX

"See? She has done nothing to your brother," Phil points out as Natasha rounds the corner. Her eyes flick between him, Thor, and the shorted out lights over head. Phil smiles reassuringly.

Thor settles back on his heels. Risky, Phil knew, to mention 'Borson,' to give any indicator of what Baldr had told him and what he's put together. But it did what it was meant to.

"What is it?" he asks Natasha.

"Bruce. He wants to let the Hulk out. We need to go." Her eyes land on Thor again. "We'll need your help."

Thor hesitates, casts one last glance at the doorway Natasha just came through.

"You agreed," Phil reminds him. "You agreed that you would aid us if we found your brother. We've upheld our end of the deal. We aren't hurting him, only trying to get back what is ours."

"Come, Lady Natasha," Thor rumbles, not yet giving away what so far only Phil knows for sure, twisting on his heel and cloak sweeping behind him.

Natasha eyes the two of them; Phil tilts his head towards Thor's retreating form.

Once they're both gone, he waits a moment, then enters the door Natasha just left.

"Agent," Loki purrs as he steps into sight, smile mirror to one Phil was looking at only a few hours ago.

XXXXXX

"I'm not trying to attack you," Bruce says— _snaps_ —and has to stop to take a deep breath. Tony keeps going near the spear, and his head feels like it's being split open with every throb. "We need to know what you know. It might help."

Tony doesn't flinch at least. He's too focused on himself, on whatever it is he thinks is there between him and the two brothers from another world.

"There isn't anything to know. Right. Okay, so I knew them, met them in Chicago, but that's it, this is the first time I've seen them in years," Tony says, words rushing, when suddenly Thor and Natasha burst into the room. Tony stumbles back towards the spear, Natasha is moving towards him, and the spear _shrieks_.

_Smash break destroy destroy_

Then Steve is there and everyone is arguing around and around— _smash_ —and why won't they just be _quiet_ and Steve is looking at him in concern and the _noise_ —shrieking whining and sixteen sounds as one, some high-pitch future scale that shouldn't _exist_.

_Destroy destroy destroysafetysafedestroy smash destroydisappeardestroy destroyfrozendisgustingthingdestroybreakburn Raaaagnaaaaaaroooooo_ —

"Bruce. Put the spear down."

There's silence but for the roaring of the Other Guy and the whine of the spear. He looks down and his hands are curled around it; it fits like it's meant to be there. He takes a deep breath in; lets it out. Everyone is staring at him.

_Bringer_ , it whisper-sigh-purrs in his grip, caress and a wide, gracious smile.

He sets it down very carefully on the stand. Some collective breath ghosts around the room. His hands are shaking.

Everything _shrieks_ , explodes and shudders, twists and tears and he's drowning: _anger hate_ _ **loss**_ _rage destroy destroy smash smash break_.

Roars and lunges for splash of red.


	11. P

**Notes for the Chapter:**

> math pr0n: P is a fancy way to say prime. If I say **P** that means the set of all primes.
> 
> 11 is a prime number.
> 
> There are infinitely many primes (as proved by Euler's Theorem, and several other really smart people through history), which is pretty cool. Some primes can have their digits added together to make another prime, like 23 (2+3 = 5, which is prime) or 11 (1+1 = 2, which is the only _even_ prime). There are cousin primes, which are the first prime and the prime plus 4, like 7 and 11 (7 + 4 = 11). Some primes become another prime when their digits are reversed, like 11 and 31 (13 is prime and 11 is also prime) and those are called Emirps (prime spelled backwards). Sexy primes are the first prime and the prime + 6 (like 11 and 17; 11+6 = 17). There are prime triplets, which are (p, p+2, p+6)or (p, p+4, p+6), like (11, 13, 17).
> 
> The largest known prime is 2 to the 43,112,609 − 1 with 12,978,189 digits, and there is no known reliable way to predict where a prime is or how it will fall, which is part of why primes are always so much trouble and yet also so very very awesome.
> 
> I have a lot of feelings about primes, and know no good way to put them in the story other than to have prime chapters cause trouble and be generally linked (I say generally, because our first chapters were more interested in the Fibonacci sequence) by the appearance of a certain person who always seems to cause the most trouble on primes. A little meta, and I don't even care. I have all the prime!feels.

_If_ Phil had had any doubts left whether Baldr was mostly telling the truth, they evaporate under Loki's reaction to the name.

 _Surprise want confusion desire love hate lust loathing_ and then Loki blinks, looks at him, and smiles widely.

"How _is_ dear Baldr?" Loki asks.

XXXXXX

As soon as the first explosion rocks the ship, Bruce _changes_.

Natasha is already running before he's finished, can hear roaring from behind her.

 _This is what he wanted_ , she realizes. It's what she would have done, if she wanted to find out more about her targets.

She races down a walkway that should be too thin, can feel it creaking and swaying as big and green _rage_ chases after her.

Everyone in the kettle, put it under pressure, and see how they react. _Testing_. Find the missing link.

Solve for X.

The Hulk smashes part of the walkway down and she lands in a tumble, rolls to her feet, and _runs_.

XXXXXX

A second explosion rocks through the hellicarrier. Steve braces himself, glances over at Tony.

"That's from the bridge. We've still got a little time, but if they take out another engine we're toast."

Steve has no idea what to do. But the way Tony's eyes are searching the air, he does.

"Do you have have a plan?" he asks. Tony looks _surprised_ he'd be willing to listen, and Steve shoves back guilt for his words from earlier.

"Yeah. Need to get my suit. Let's go."

XXXXXX

Nat sucks in a breath as she hits the ground, feels metal pinning her down and resists the urge to swear. Wasted air—she needs to save it for getting out from underneath the metal.

A hand grabs hold of her ankle. She glances back and meets rage-filled eyes, flicker of blue in the background.

Everything goes blinding white. There's nothing but sound—electricity and screaming and laughter.

The laughter is what is most frightening, more than the sound of the Hulk even _angrier_. It's joy and bitterness and loss, laughter to keep from crying, and possible gods should not make such noises.

Natasha can see the Hulk roar at Thor. Thor grins wide and roars back.

She slips away. She hears another explosion from the bridge—she's needed there.

XXXXXX

"Find him. Get him out."

(He's so _close_ to bright flickering (origin) center, can see-hear-taste it, but his path doesn't go there, it goes here, circles just at the edges.)

There's a chorus of 'yes, sir's and Barton eases carefully around the walkways. He can make out a bit more of the bridge through the cracks and lines up another shot.

( _Do you trust me, goshawk_?)

Someone slams into him from behind and he twists and meets grey-grey eyes that are wide in surprise.

(This is it, this is his drop—his heart thunders, he does not want this, he doesn't want to _fall_ , to lose him(her) no no—

He lashes out and moves in to stop her because he _doesn't want to drown again_.

( _I won't let you fall far, goshawk. Trust me._ )

 _ **No**_.

He doesn't want to fall at all.

XXXXXX

_Rage anger smash tear, smash everything, smash_ green _fastest, first_ —

_stinging tearing buzzing_

screams rage

_and it doesn't stop_

_smash tear rend smash_

leaps

_rip slipping tearing grinding_

destroy

XXXXXX

Thor breathes ragged and finally, _finally_ , walks into the room where Loki is, where Loki is walking _out_ ; his brother freezes on seeing him.

" _No_!" Thor yells, charges—and passes through, stumbles into the cage. He spins around and electricity sparks from his fist as he slams it into the door.

"You always did fall for that," Loki says, revealing himself, voice disinterested. "Though, to be fair, it has been quite some time since you've needed to keep it in mind, hasn't it?" He tilts his head to the side.

"Don't do anything stupid," a polite voice chimes in; Thor notices Agent Coulson standing there, a weapon in hand. Loki looks at him and Thor sees it, knows as well as he knows his own name, what will happen.

Loki has never taken well to threats.

"Loki, _no_!" he yells as Loki vanishes with a flicker twist of shifting math.

Stares helpless as Loki whispers in Coulson's ear, sharp dagger tearing through the human, before he tosses him aside, kicks the gun across the floor, and turns back to Thor.

Never. That, then, has not changed.

"Now," Loki says, voice blank as his face, something dark in his eyes, "where were we?"

XXXXXX

Tony hovers in the air, cuts away debris.

He needs to focus. His thoughts keep twisting though, twining

( _red ink, x sub n-plus-one equals x sub n squared,_ _writhing beneath his skin, Loki Thor dead and not, broken, haunted, wanting_ safety _in brilliant sick eyes_ )

but he shoves it away.

"Steve, that standard control unit can reverse the polarity long enough to disengage mag—"

"Speak. English."

( _Red ink and alive_ )

Right. Fuck.

 _Focus, Tony_.

"See that red lever? It'll slow the rotors down long enough for me to get out. Standby it and wait for my word."

"Ok. I can do that."

( _Where is he, what is he doing, need to g_ —

"Stark, another engine is down. We're losing altitude."

"I noticed," he snaps, and starts to push. Metal grates on metal.

( _Thought grinds on thought_ )

Focus.

XXXXXX

His eyes are all wrong.

She ducks beneath a swing of his bow, grabs hold of it and slams a knee into his side. He stumbles back, grabs her hair, and pulls. She slides with the motion, throwing him off balance, and twists out of his grip.

His eyes are cold, angry—

grabs the knife before he can slit her throat, struggles against his weight

—and _terrified_. Cornered, rabid animal _fear_.

He grabs the back of her head and she bites down on his forearm. They spring apart and in that single unguarded moment she punches him in the face.

His head snaps back—

for a second she is _terrified_ she has hit him too hard

—and he groans, staggering, eyes rolling. He leans against the railing, grasps it tightly as if he's falling, drowning. She slams his head against the metal and he collapses. Twitches and then lies still.

But breathing.

(And childishly, she prays that is all she needs to do get him back.)

XXXXXX

"Loki, please. Do not do this. I do not know what you have been promised, but Brother, please. Come home. Give up this mad plan."

 _(Home_.)

Golden halls. _Fire fire firefirefirefire_. Positive in place of negative.

 _(Home_.)

He laughs. He cannot help it. He laughs until tears roll down his face, brushes them away with one hand.

"Oh, you _are_ a fool. What is there to return _to_ , Thor?"

Thor is staring at him, face breaking, and Loki chuckles again.

"Mother. Father. Everyone. Loki, you are not well. Please, we can help you."

He stops moving.

( _They are there, all of them._

_He dies._

_No one does anything._

_They watch him_ _ **die**_ _._ )

"Help me?"

"Yes."

"Why now then?"

"What? Loki, you were lost. You fell! I had to find you!"

Nothing. It means nothing to _him_ , precious golden ratio, precious golden _Thor_. He goes entirely still.

"I called."

(Remembers: _Negative slope outside of Yggdrasil. Quiet, numberless._ )

(Remembers: _calling and spun numbers and unable to find {0,1,1,2,3,5...} and no answer_ )

Thor is staring at him, and there, again: _guilt_. Like when Loki first opened his eyes from screaming splitting _stop_ and met thunder-blue eyes.

 _Guilt_.

"I _called_ you. I called you the old ways and _you did not come_. I remember, Thor, _brother_ , I remember _pain_ and _ice_ and _dying_. All of you. _All of you were there_. Where was your _help_ then?"

"Loki, you—"

" _Tell me!_ "

Thor goes silent. Golden Thor, Thor who always has come, Thor who _abandoned,_ Thor who _watched him die_ , his Thor, his not-actually-clever Thor. It twists at him, tears, is an echo of square root of negative one divided by zero.

He presses a hand to the transparent wall that separates them. Ice flares and cracks along; his skin changes blue and cold (negative in place of positive).

"Is this why?"

Thor's eyes widen and he takes a step back.

"Tell me, Thor, is this why?"

"Loki, what trickery is this? Stop it. Please. You are my brother and I love you; I have searched for you all this time, and I swear to you I did not—"

" _You watched me die_!"

Everything is falling apart again. Missing missing pieces, and he cannot, he cannot, and now—goshawk gone, familiar comforting goshawk (closest to T ( _T = ?_ ) that he has goshawk), all as planned.

Yes. Planned.

He turns away.

"They think us gods, Thor," he says idly, "and I survived well enough my own fall."

He mimics the motions he saw Fury use earlier. Air rushes in, whips around, and his skin bleeds back to familiarity.

He looks up, meets thunder-blue eyes equal parts horror and guilt.

(Wishes it were _fear_ , so he could use it to string himself back together.)

"Let us see how you take your own."

He stares distant at the empty space for a few minutes after Thor is gone, after the cage has fallen. All is nothingness again, zero.

Null.

( _Fractal recursion, T = ?_ )

"You won't win," a weak voice says. Agent Coulson, still clinging to life.

He does not want to _win_ , only wants what he has _lost_.

"And why is that?"

( _Thor, spirals, the limit of emotion as L approaches Fequals 0, primes_ )

"You lack conviction."

He stares at the mortal.

(He still does not know what T equals. It is not Thor. Not his not-actually-clever Thor, Thor who watched him _die_.)

(T is here. On Midgard.)

( _You think you know pain? He will make you long for that so sweet as pain_ and soul tear that is unquantifiable, aching _worse_ now somehow for Thor's betrayal)

"Conviction," he repeats, slowly.

Remembers plans, discovering what he _needs_ to stop those who would take Midgard from him (leave him with pain and soul-tear and _loss_ ).

"Yes. Conviction." There is what he came for, even if he has _lost_ more for its gain.

No matter. He will get it back.

He grabs Agent Coulson, shoves his hand in blood, and creates a dead duplicate, mirrors Coulson's equation in all but that oh so necessary spark of life, so that they will find him and have their precious conviction.

And safety. Yes. He must ensure _safety_ as well. He still has _plans_ to enact. He mustn't let this stop him. He has suffered _worse_.

( _For a moment, a blink, he remembers:_

Light hitting a reflective surface at 67 degrees from the southwest, voice D chord rumble, one point two liters consumed, two over seven, just a rather very—

_He claws at the fading magic and whorls of light, tears apart sound of tau, reaches, reaches, falls into the floor, and grasps for fading—gone._

_Gone._

_Loss equals_ _ **this**_ _._ )

So much worse.

"You," he says to the real, breathing Agent he holds one-handed, "know where Baldr is. You have _use_."

He smiles.


	12. (0,0)

**Notes for the Chapter:**

> Hello hello.
> 
> Old math refresher: (0,0) is called the origin in graph theory, and is the central point on which everything else is referenced to.

He finds Coulson where he expected. It's the first time in years Fury has seen him not perfectly dressed, even if he still looks unflappable as ever. He ignores all the blood, crouches down, and checks Coulson's pulse. Just to verify, just to be sure.

Nothing.

Fury bows his head and rests his forearms on his knees. He closes his eye for a few minutes and lets himself mourn for the only person he very nearly trusted. For a minute, he lets himself be only Nicholas Fury, friend of Phil Coulson, instead of Director Fury, head of SHIELD.

Then he opens his eye and puts the role back on. He studies Agent Coulson and he thinks. This might be the push they need, the traction to bring them together; he has no doubt that Coulson thought so when he went alone to confront Loki.

Fury stands and heads for Coulson's locker.

XXXXXX

Thor pulls himself up from the field of flowers he has landed in. HIs hammer is not far, perhaps the only reason he has managed to survive the fall; the whole of him aches.

( _You watched me die!_ )

He does not go to Mjolnir, not yet. He looks up at gathering storm clouds. He wonders if Heimdal is watching, if Heimdal has told the King and Queen what Loki is now.

( _Is this why_? and slowly spreading blue)

Loki is not well.

Loki is not the same.

( _Tell me!_ )

And Thor knows that if he does nothing that Loki will lash and destroy for his imagined slights instead of the real ones. Loki is not well and has not been for years now; foolish of Thor to hope otherwise.

He looks to where Mjolnir rests a few yards away.

His brother will not come home willingly. Will not give up because his mind is torn and he has strung himself together with hurt and false memory.

And if he goes against him, if he takes up Mjolnir against the very being who has made him worthy enough to carry it all these years...

_If_.

He walks to Mjolnir but does not lift it. Not yet.

_If_ he takes up Mjolnir, _then_ he admits that he might need kill Loki to stop him. Loki lost seventeen years, Loki of quick smile and quiet laughter, Loki of math and magic, _Loki_ —Thor's little brother he once carried upon his shoulders through the fields of Asgard, small hands twined in his hair and trusting laughter ringing the air.

Loki, so _changed_ that he would take a realm irrespective of the cost.

Thor reaches down and grips Mjolnir's handle.

XXXXXX

Barton is alone when he wakes.

His head throbs and for a moment he wonders how much he drank the night before—

_green-green eyes and paths that branch endlessly, fractals and Lo(Nat)ki, safety, ordering and enjoying it because it means he(she) will rest, sunflowers and humming and dancing where no one can see_

He feels sick, shifts so he is sitting on the edge of the bed and presses his hands to his face.

The door opens; he looks up and there is Natasha, grey-grey eyes and vibrant red hair.

(Natasha he nearly lost and he pushes back the thought that _he_ helped Barton not lose more, pushes back echo of loss in _him_ )

Natasha sits next to him.

"How are you holding up?" she asks.

He wonders why Natasha didn't hum before she spoke, wonders if this is something new. Wonders what he missed, what changed, and how much more is different.

"It feels like I've been unmade. Do you know what that feels like?"

"You know I do."

(They both do, _him_ and her; the surge of sympathy and understanding nearly makes him scream.)

He clenches his hands into tight fists.

"We'll take care of it."

"I've got an arrow for his eye."

(But part of him wonders if he'll be able to release it.)

(Nat and Loki, Loki and Nat— _Bringer_ and _hope_ and _everything_ ,sick and tangled in his head.)

Natasha puts a hand on his wrist.

XXXXXX

"You okay, son?"

Bruce opens his eyes to find himself in a pile of wreckage, steel and concrete digging against his skin, and his stomach drops as he realizes what this means. He leans up gingerly.

The source of the voice is an older man, a janitor based off his push broom he leans against. Bruce wonders dully (always so little _anything_ after these changes) how much the guy saw.

"Yeah."

There's a pile of clothes sitting next to him; he frowns at it.

"Had a spare set. Go on."

It's like he has found the only person who won't panic. Bruce grabs the pants.

"You an alien?"

"Um... what?"

"Alien, you know, outerspace. Not from around Earth."

"No." That might be easier (images of Thor and Loki flash through his head; maybe not).

"Then, son, you've got a condition."

Bruce buttons the pants, trying to hold back a chuckle, staring at this guy.

"Yeah. Yeah I do."

The janitor—Harold, according to his nametag—lets Bruce get dressed the rest of the way in peace.

Bruce thinks about what he knows. Loki has almost certainly taken whatever he was after and moved on. He needs to regroup with the others, preferably somewhere they can stop Loki; but where?

He remembers Tony's expression.

( _I met them in Chicago, years ago_.)

"How far is it to Chicago?" It's a hunch, but Bruce has long since learned to trust his instincts.

XXXXXX

Tony walks down to where the cage used to be, where blood stains have been cleaned away, where for a few hours Loki was contained. It's empty-quiet.

He doesn't understand.

It's his Loki, has to be, the tattoo is there if hidden, but _his_ Loki is laughter and joy and _love_ , _his_ Loki races across town and the trouble he causes is always a scene more than it harms—mischief.

_His_ Loki does not kill people, does not have a shatter-glass desperate-hungry- _save me_ look to his eyes, might be god-like but isn't _this_.

It doesn't make sense.

And Coulson.

Maybe he didn't always like him, but Coulson is, was, a good guy, _actually_ good where Tony has been just trying to make up for things (for not getting Loki to take him to the airport that day, for all the lives he's ruined, for never being enough and knowing it). He's watched the footage with Steve when the all too-brave Coulson went alone to confront Loki, to try and keep him in place, and the still blank of Loki's face (but _his eyes_ , angry and vicious and _no-one-will-hurt-me-again_ , Tony _knows_ that look) is the last thing they saw before Thor's electric emotion finally killed the cameras. That Coulson is gone, that his constant almost-terrifying-calm is _gone_ , and by the hand of someone Tony loves...

(because he does, because it's _his_ Loki, fractals and JARVIS and that one perfect summer)

He hears Steve come in and tries to focus again.

"Are you holding up?"

Earnest, kind Steve, the only one who's still making sense. Still acting the way Tony expects.

"None of this fits."

Steve nods and waits for Tony to go on.

"None of this. It's all so out-of-character for him. Loki." He stares at where the cage used to be. "He's patterns and routines, mischief but not _this_."

"You know him?" Steve says, surprised and sharp. Right. Tony hadn't told him, hadn't told anyone.

He doesn't care.

"Seventeen years ago. Loki Borson."

There's silence. Tony walks a slow circle around the room.

"Putting aside you kept that from us, because that seems to be something everyone is doing and it won't change anything, you're... look. If anyone knows this, it's me, so don't get upset, but you're stuck in the past. On what he was. Thor was doing it too, told me all about Loki and you could see it."

Tony looks at Steve and for the first time sees the sincerity and kindness that inspired people to spend seventy years searching.

"People change. Times change." Steve's eyes are hurt and guilt and Tony hates seeing a mirror of himself. "Maybe some is still the same, but you don't know that. You're, look, here, something science-like, you're going off old data. It's been seventeen years."

Steve looks down and away; he would know.

Old data. Elementary. It feels like Tony's mind has suddenly caught fire. No wonder he can't reconcile his Loki with this Loki—he's missing too much, there's stories and events in Loki's desperation he can't understand because he doesn't know what happened while Loki was gone. Some things are the same (tattoo ink rising to meet his finger tips).

He remembers Loki's slow spiral while he spoke with Fury.

"He wants something he lost," Tony says, because he knows the look in Loki's eye. Steve is looking up again, emotion contained. "Chicago. That's where his family that still lives is, where Baldr is—Coulson mentioned him, you saw Loki's face, he's got to want to know more about him—it's where he was when he was human. And Stark Tower is there, it'll have enough energy to jump start the portal Clint says he's trying to open."

( _Where we met._ )

"Then let's move."

It's no answer but it's a plan. A way to get an answer.

Better than nothing.


	13. as L approaches B

**Notes for the Chapter:**

> Right. Meanwhile, now that we are on a Fib and a prime, we have someone we need to meet.
> 
> (did you notice we met everyone during the initial Fibonacci sequence chapters?)
> 
> math pr0n: 'as x approaches y' is a phrase used to speak about limits, which we touched on ages and ages ago with Frigga's fic. It's basically describes when we are examining a given equation's behaviour as it approaches a specific point. For instance, you see the phrase "the limit of emotion as L approaches F is 0" which basically is a fancy way of saying that as Loki approaches/deals with Frigga, the behaviour of his emotions tends to flatline/calm. Tada!
> 
> warnings: suicidal tendencies, blood

**Chapter 13: As L approaches B**

People are sometimes born with old souls.

(When he is born, he _screams_ , and already flashes of blood and rebirth press into his head, colours he does not understand but which tear and tear and tear, all of it swirling around _love_ and _hate_.)

Sometimes, cities are born old as well.

(He remembers: dirt and mud and smell of sheep, laughing and running across hill and dale, flash of brilliant green eyes and a smile to mirror his own.)

Chicago is _old_ , in its own way, built upon blood and bone and ash, born and reborn again. Its buildings rest atop other buildings sunk deep into the ground, its history blood spilled on blood and sparked with revolution, renovation, and rebirth.

(He remembers the stab of mistletoe, sharpened and biting and _pain_.)

(Always always he encounters this: green eyes and a smile to mirror his own, his twin in everything but eye and purpose.)

Baldr quite likes Chicago, nexus of trade, history, _cycles_.

He stands in his office, overlooking the expanse of the city, hands clasped loosely behind his back. Waiting. He can feel and sense

( _once a long time ago, he was an artist, his lover and patron a princeling, green eyes sparkling fervent with worship, love, lust, both drowning and devouring the other, drunk off paintings he created full of golden halls and perfect fields_ )

the shift of energies, twisting plans that align and realign constantly, and all of it a hair's breadth from spiraling out of control.

(somewhere else he shifts, lashes flutter against his cheeks, asleep for long and long and longer, asleep for _centuries_ ; it is dark and dim gold and somber in his room that he cannot see. But once, he did not sleep and if (if if if) _he_ does what he is _meant_ (his _purpose_ ) then sleep will be waking and then finally _silence_ and _black_ and _peace_.)

He is alone.

Then he is not.

Baldr turns and he meets green-

( _he looks up at that voice and meets green eyes and_ _ **memory**_ _crashes in his skull and his mouth parts_ )

(in every cycle and some mortal lives (but not every mortal dream; those dreams where he doesn't he _weeps_ at loss he does not _understand_ , at memories that _press press press_ from thousands of mortal lives before and wonders _where_ those eyes are, _where_ the figure that haunts his art has vanished to) he meets green eyes and he _knows_ what they mean and he _loves_ and he _hates_ and he _**remembers**_ )

( _smell of mistletoe and bleeding and_ _ **hate**_ )

( _mirror smile and laugh and_ _ **love**_ )

-green eyes.

"Loki," Baldr says and he smiles ( _he smiles (he smiles (he smiles at this stranger) at this lord) at his lover_ ) at his other half.

"Baldr," Loki purrs, stepping from shadows into glimmer of light that spills from this old city into the office, face all sharp angles and planes, eyes near fevered, bright and sick and twisting sliver of blue floating over green.

(He remembers: _red blood, white bone, silver knife, and a smile, a beautiful, beatific smile, on sharp features with fever bright green eyes and gasping final_ _ **release**_.)

(until it begins anew)

(until once again green eyes meet his and take one of his away, send him to mortal dreams that he cannot forget _ever and ever and always_ and he _hates_ but he _loves_ because that smile and those eyes eventually return and then there is _peace_ once more.)

But that is not this moment.

"I hear," Baldr says to Loki, mirroring the small smirk on Loki's face, "that you are _looking_ for something."

Loki's eyes flash, blue writhing sick ( _chains_ and Baldr would rip them away because they are _limiting_ him, and that is why this moment is not _blood_ and _love_ and _release_ ), and Loki's smile falters.

"You _know_ ," Loki snarls, suddenly in front of Baldr, grabbing the front of his shirt, eyes furious and wanting.

(He remembers: laughing in golden halls at his mirror, his other half, his lover and his friend, laughing _at_ , and the furious hands that pull him forward.

It was only a mutt, he says, only a mutt Lo-ki, _love_ , taking vicious pleasure in hurt-anger-darkness in those eyes because he _hates_ )

(But that was not this cycle, no, this cycle he and Loki were together _elsewhere_ , twined in heat and passion and _forgetting_ that particular hurt, when Fenrir was taken and chained, because he _loves_ as well)

Baldr only smiles at Loki, ever at ease, and runs a thumb along a cheekbone he knows as well as his own.

"Of _course_ I know, Loki. You're my other half, the end to my beginning, how could I _not_? Of _course_ I know, someone needed to watch after your things while you were away." He keeps smiling, keeps running his thumb along that cheekbone, and Loki relaxes, hand still twined in the front of his shirt but no longer pulling, and his face

( _brilliant green eyes and a hand keeping his face in place, child's face twisted into anger-hate-rage_ )

stills again. Uncertain.

(before this is done you shall beg me to kill you, dearest golden god, _and he laughs at that, laughs and laughs because his every moment is begging for these dreams to end and for blood-darkness-_ _ **peace**_ )

Loki lets go; Baldr steps back, putting his hands in the pockets of his slacks, and tilts his head to the side.

(One time, many times, in many many of his dreams, they cut their hair and wear the same clothes, so that all that separates them is their purpose and their eyes.)

"You surely have questions, dearest fire."

But Loki, oh Loki, has never been taken in by his smile, too similar to Loki's, and knows what it _means_.

"Not of you."

"Of course not. Of course not. You never do, and I suppose that is fair enough." He steps close to Loki, eye to eye, breath brushing each other's lips. "Even if I _know_ what you _need_." He circles around Loki, trails one finger up his (left) arm, to his shoulder, where the dream brand (dream brand he did not expect but it does not _matter_ because Loki is _his,_ and Loki cannot escape his purpose, no more than Baldr can escape being drawn to that fire which gives him darkness) still writhes beneath the surface, chained by blue and aching to slip free. "What you _lost_ ," he whispers, lips brushing the shell of Loki's ear.

Loki goes still; Baldr smiles.

(So very very close to blood and bone, peace and darkness.)

(Only a little push.)

( _Old_ and _cold_ and _dead_ shall do the rest.)

He runs his hand along Loki's neck, pushes aside his hair and traces patterns on flesh (patterns he has traced in hundreds of dreams and lives and cycles on this same expanse of skin, with blade and fingertips). Loki's muscles tense and twitch beneath the skin, but he has not moved (caught in memory he does not grasp, because _he_ cannot _remember_ ).

"I will tell you, fire to my dark," he whispers, rough purr in Loki's ear, then draws back a little, presses a kiss to the top of his spine, trailing kisses up Loki's neck and to his other ear, Loki's back flush to his chest now, Loki's breath caught

(blue blue chains rattle and shriek, tattoo brand writhes and presses closer to the surface, heat against and through armour burning the tips of his fingers)

and head tilted back.

"Why should I trust you?" Loki demands, but he does not move. Baldr takes his other hand from his pocket and rests both at Loki's waist.

"I tried to get help, when you died. I wanted to save you. Don't you remember, Loki?" He bites the lobe of Loki's ear, licks trickle of blood as Loki's eyes search (knows that he does not remember, that he cannot remember, and smirks). "I _love_ you, Loki, more dearly than anyone else."

Loki wavers at the word ( _love_ ); Baldr holds his weight so he does not fall, continues to press kisses to his ear, whispers soft nothings to soothe him

(because if Loki kills _this_ dream it will be _too soon_ and _not enough_ )

and before he recovers (before he can _hear_ ), Baldr adds (because he _hates_ ):

"Tony Stark is who you lost, firebird, he and his _fractals_ , and oh what _care_ I've taken of him."

Loki's eyes roll, nearly all blue, pained and lost, and a low _wanting_ whine escapes his throat.

(And this, _this_ is not something he remembers, never has anyone so affected _his_ Loki, but he does not care, because all Loki is in his arms now is want and desperation and _trust_ )

He waits, goes back to whispering soothing nothings, until blue fades back to a slender slender web (so close to snapping, but it is not quite _time_ ; She will see to that), until Loki rasps:

"Tell me."

Lips brushing against Loki's ear, he whispers of a text, rare and hard to find, that ( _trust me_ ) Loki will need one day _soon_ ; he whispers of a tower near the center of the city ( _trust me_ ) he can use _now_ ; he whispers of a man in an iron suit to question who knows ( _trust me_ ) what Loki has lost.

A smile curves his lips as he whispers, fingers digging into leather, single blue eye dreamy and honest, swirling dark with _hate_ and _love_.


	14. Probability of Finding T, Given C

**Notes for the Chapter:**

> This is called I woke up at 3am. On a Saturday. Why?
> 
> Because my body hates me is why what did you think I had something to do. What a jerk right? Well, you benefit-here you go.
> 
> math pr0n: Probability. Oh probability. How do I hate thee? Let me count the ways. I hate thee to the depth and breadth and height my soul can reach.
> 
> Anyway. Enough sonneting over here. Conditional probability means the probability of some event based off the probability of another event. Example: you have a bag with 2 red balls and 3 blue ones. If you pull out a red ball and don't put it back, then the probability of the next ball you pick is going to be altered accordingly. The way you say this is "the probability of event A, given event B".
> 
> Everyone who figures out where Lenneth is from will get a cookie. Not a real one. Just. A soul cookie or something.

**Chapter 14: Probability of finding T, given C**

They make it to Chicago just in time to see the portal open.

Of course.

There wouldn't be much use for people like them, Steve thinks, if things were ever stopped _before_ getting this far.

He glances over to Tony and part of him wonders if this is smart, bringing him in, but they don't have much choice. They need all the help they can get.

"Can you do this?" Steve asks.

Tony's face is a blend of shock and half-guilt.

"Course I can, Capsicle. You already said it, didn't you? Things are different now."

It'll have to be enough.

"Right."

And then it's all Captain, the last of Steve Rogers put aside for now.

"Tony, you get the skies, try and run interference near the portal. Clint, you've got the best eyes; get somewhere high and call shots. Natasha, you're with me, help me start getting civilians and local forces organized. If anyone gets a bead on Loki, take it—we need to get that spear to stop this if what Clint says is true. We can't count on Thor or Bruce to show up. Understand?"

There's nods from the other three.

"Right. Let's move."

 

XXXXXX

It is utter chaos in both street and sky.

(A smaller version of something _after_ , something he never sees but _hears_ about, later, when he is pulled from darkness once more (when everything begins anew).)

He smirks as he hears the familiar rumble of a particular type of thunder and sees lightning flash down a few blocks away.

"You have to let him make his play," he explains. "He doesn't understand our prince, not how I do. Let him nudge; the rest will fall into place and we _both_ get what we want." He smiles genially at the shrouded figure next to him.

"I hope," She says, "that you are right."

His smile widens, all teeth, blue eye sparkling mad-happy- _wanting_ , other milky and dead.

"Trust me."

"Sir? It's time to go."

Baldr turns, the figure at his side vanishing, and looks at his secretary. She is all calmness, steel and battle-readiness that only Odin's valkyries ever manage.

"Of course, Lenneth. Let's enjoy this at a safer distance. No need to let plans unravel so close to the end."

 

XXXXXX

One moment there's a Chitauri about to bring his rifle down on Natasha's head; the next there's not.

Thor spins away from her, cloak sweeping out like a bloodstain as he throws his hammer, and two more Chitauri fall. He catches the hammer as it comes back and twists around; for the moment there are no more near them.

"Thor!" Steve calls, running over to them.

"Captain. Agent," he says seriously, eyes sparking and face somber. "Where am I needed?"

There is a roar that shakes the still standing buildings and _something_ comes out of the portal. They all stare up at it, the tiny speck of red and gold that flashes in front of it and starts to try to drag it along.

"I think Tony could use some help," Steve says faintly. He shakes his head. "See if you can keep anymore of those things from coming through."

Thor nods, starts to spin his hammer, and is gone. Overhead, the sky darkens with thunder clouds, roiling eerie and sick yellow-green.

 

XXXXXX

It's surprisingly _easy_ to find Steve and Natasha in the chaos of the fight. He just has to follow a pile of bodies. He catches sight of something huge and whale-like coming out of the portal and nearly runs into Natasha as his eyes follow it.

Steve is listening to his ear piece, and glances over at them.

"Tony is bringing it our way," he says.

Bruce stares a bit more at the thing chasing Tony.

"Right. Right. Of course he is."

 

XXXXXX

"Two on your left, Cap," Clint says, turns and fires off an arrow in the face of a Chitauri trying to get close to him. His eyes sweep the streets below; he keeps catching familiar flicker of green-white light and can't decide if it's memory or he's compromised again. Still compromised.

He's never felt so sick while fighting.

Underneath the sick, though, he's _angry_.

Now, when his thoughts aren't constantly twisting back on themselves, he suddenly can make sense of the patterns and lines, and he sees it. What they are doing, how everything is all focused on this portal and what is meant to happen. What they are meant to stop.

He doesn't want to appreciate the artistry of this chaos given direction.

Clint shoots down one of the Chitauri pilots and the hovercraft crashes, killing the other two.

"Where are you guys at, Cap?"

"Clark and..."

"Adams," Clint finishes. He sees Stark leading the giant alien creature on, dragging it towards the others.

"Right. Thanks, hawkeyes. Guys, bringing the party to you, hope you remembered to bring favours." Clint turns, and spots familiar white-green light that whirls in the air, follows it and _there_ :

Loki.

He draws an explosive arrow back and releases before the rest of him can think, before he can properly aim, before he can feel sympathy-want-loss- _protect_ that wants to swell back up.

If his smile isn't sincere when the bastard catches it and it explodes, no one but him needs to know.

 

XXXXXX

_Smash_?

Bruce stares at the giant _thing_ chasing Tony down the street, roar making his bones creak. Steve glances over at him.

"Any ideas?" he asks.

Bruce smiles a little, feels white bubbling rage pressing into his head. This isn't like before, though; no, this, he can focus.

"Sure. You might want to stand back though."

He starts to trot forward, lets his thoughts swirl.

 _Smash (defend) break (these aliens)_ and white hot rage twisting, aching, until he's nothing but _anger_. Pure focused _rage_.

He roars, leaps into the air ( _just these things now_ ), and slams his fist down onto the head of the creature.

 

XXXXXX

Tony takes a moment to watch Hulk before he zooms off, back to trying to keep more aliens from pouring through.

"Sir—"

"Jarvis, what just flew past me?"

"I believe it was Loki. Do you intend to pick up where you left off?"

"Damn right I do."

He corrects and flies after, settling on the landing pad. Loki turns to look at him, armour vanishing in a swirl of gold and eyes narrowing.

"Remove the armour."

"Is that really—"

"Yes. Say hi to your other dad, Jarv." He walks along the ledge, armour being stripped away.

He doesn't take his eyes away from Loki's; on his shoulder, the tattoo aches and writhes like a live thing.

Loki smirks, but his eyes, oh his eyes. The flicker and blue glow in them twists, shatters, and reforms; there's the tell-tale twitch of his right eye of pain barely hidden. His Loki is there, buried, but he's there, just like Clint said.

Tony smirks.


	15. Fractals

**Notes for the Chapter:**

> Oh hi. No crack of dawn update because last farmer's market was today.
> 
> Two chapters after this, then Bifurcation wraps and we start the final story of the series. Taken long enough.

Part of being able to recognize patterns means knowing when they are deviating in significant and non-significant ways.

For instance, when Loki lies, he never breaks eye contact. When he tells the truth, a maddening smirk will cross his lips as if he is lying. And when he is hiding something, pain or emotion or something he does understand, his right eye twitches, just slightly, infinitesimal and easily missed.

(This dance feels like before fractals, when it was a new bed every night and a new stranger to fight and promise over, alcohol passed like water between them.)

That all those signs are still there gives him hope even as it leaves him aching. Loki's still there, underneath it all, and something in him _remembers_. Has to, otherwise he wouldn't feel the need to circle here to Chicago, wouldn't be staring at Tony with his enigmatic smirk while his eyes do the thing they do when he's thinking, mapping, breaking down variables and storing them away.

Tony has always loved pushing things to breaking, and if that's what it takes to get his Loki back, well...

"Please," Loki purrs, smile widening, eyes lazy and dangerous, "appeal to my humanity."

(That would be too straightforward, Tony thinks, and hardly elegant. They've always preferred elegant solutions.)

Tony walks to the bar, returning the smirk, ignoring how his tattoo aches and burns.

"Actually, I'm planning on threatening you."

One eyebrow quirks (just like it used to, when someone managed to amuse Loki).

"Should you have not left your armour on for that, Iron Man?"

Tony reaches right handed for the bottle of scotch, left hand burning white and nearly numb.

"Oh, sure, sure, but it's seen a bit of use. Do you want a drink?"

Blue flickers in Loki's eyes

(" _Not going to use your name, then?" and the flick of enchanting smile like a honey coated knife._

" _Sure, I can, but it's seen a bit of use. Do you want a drink?"_ )

and his smile creaks a little, more teeth than smirk.

_There you are_ , Tony thinks, but he keeps it off his face.

"Stalling will not change anything," Loki says, almost snaps (it's in how his teeth click a little too sharp, how his eyes have narrowed, in the restless pacing he's begun, in his face easing to blankness).

"No," Tony corrects, grin all teeth, pouring himself a glass. "No. Not stalling. _Threatening_. Are you sure you don't want a drink? On me?" He cocks an eyebrow, oozes self-centered charm.

(" _Are you sure you don't want a drink? On me?" He cocks an eyebrow, oozes self-centered charm._

_Green eyes shimmer and twist infinite, catch his gaze and hold it, then he leans forward, lips brushing soft against his ear, a hand slipping beneath his suit coat and teasing along his stomach._

" _That would be rather inefficient way to drink, don't you think?"_ )

Loki takes a half-step towards him, a frown flickering so fast that if Tony didn't know that face he would have missed it entirely, then turns away. Tony slips on two wrist bands, prototypes for the homing suit, and hopes he doesn't need them; his left hand is nearly numb, but Loki doesn't turn around before Tony manages to get the right band on. He picks his drink up and comes around the bar.

Loki's eyes twist blue, ripple and shimmer, green just beneath the surface.

(This is what has always been: push until things _break_.)

(He hopes Loki does not break when what has his eyes all wrong does.)

"You and your band of merry heros cannot stop this," Loki grates out, eyes lidded, and there, there, clench of his jaw. All so subtle, but Tony sees it.

"You could."

The words hang in the air, Loki openly flabbergasted at the thought. Tony stares at him seriously, taking an even sip of his drink. He can't feel his left arm anymore, nothing but the burn and swirl of the equation on his shoulder.

(Loki is so close to the surface, so close to _free_ instead of this wrong-eyed demi-god, and all Tony wants is that laugh again, that smile again; _want_ a sharp ache in his chest, buzzing impatience, because he can flirt and break but he's tasted _better_ , tasted fractals and drowning and breath brushing against his lips while their limbs tangled up; this might be close but it's not Chicago.)

He _wants_.

"I mean, you could. You certainly seemed to like humans well enough your last trip here. We only fucked half Chicago's elite together."

Loki stills entirely, stare digging into Tony, then he snarls, eyes flaring bright and blue wash, step half-staggering as he starts to move towards Tony. He shakes his head, trying to clear it, then looks up again; Tony watches, breath held—Loki's eyes are all green now, only faint rime of ice around the pupils. He smiles sardonically.

"Don't you remember?"

Loki chuckles darkly, paces forward and around Tony; Tony follows him with his eyes; there's a span of half a breath where their eyes don't meet and Loki starts to talk.

" _What_ ," Loki purrs, dark and angry, pushing back as much as Tony's been pushing against, "would give me reason to remember mere mortals? Let alone _you_ , so little threat I've no reason to even recall your name?"

It's as calculated as every barb either of them ever threw, every smile they've ever given to other people, defense and poison, and it _hurts_.

"I held you in my arms and watched you _die_ and you want to ask why you should remember me?" Something dark stirs in his chest beneath white hot _seventeen years_ and he wants to destroy. "I could map every inch of your soul and you could do the same with mine, I knew the whole of your body and you knew every single angle and curve of mine, and you want to know _why_ you should remember me?" Loki's eyes flicker blue, pain open on his face, a hand moving to his head as he sways, but Tony keeps pushing, voice furious. "Is it some joke, so easy for you to forget, so easy for you to lose, just another stroll among the mortals?" He chuckles, barely restrained anger, and the glass in his hand shatters, scotch burning the cuts as he closes it into a fist; he hardly notices. " _Fractals_ , Loki, _Loks_ , fucking _fractals_ , the light on the lake at sixty-seven degrees, sunflowers, Fibonacci numbers everywhere we looked, how you hum before you speak and how you scream when you come, is that all just some _dream_ you can forget?" He shoves Loki; Loki takes a step back, pain so stark on his face it near breaks Tony's heart, but it doesn't _matter_ , because it's his Loki and his Loki's _forgotten_ while Tony's been here, unable to forget. "X sub n-plus-one equals x sub n squared plus c, do you _remember_ that, _Loks_ , or is it just _nothing to you_? You _understood_ me, you _loved_ me, and was it all some _fucking dream to you?!_ " He moves to shove Loki again.

Loki's hand flashes out, grabs him by the throat and draws him close, eyes alien, brilliant blue, blue of the sick and the blind.

Eyes _panicking_ , rabid animal _fear_.

All the anger dies as Tony meets those eyes, that terror and panic and _pain_ , and then Loki roars, gaze tearing away and glass is shattering around Tony, free fall and shock as the air whistles past.


	16. Chapter 16

**Notes for the Chapter:**

> This one doesn't have a title. I'm sorry. It's rather long for a chapter if that makes you feel better? Also one of my favourites.
> 
> But I figure I'd update this one now, and on Christmas Day I'll do the last chapter of this story. (remember, we've got one last story in IFF to go after this, so there's still a bit I need to resolve that won't resolve during Bifurcation)
> 
> I love all of you. <3

There is something falling; he ignores it

( _no, look_ )

then catches flash of red-gold chasing after the speck

( _catch him!_ )

He growls, shakes his head, and begins to run, knocking things out of his way as he goes. Then the man is nothing more than red-gold and hovering above the ground, zooming off. He roars, irritated, looks up at where he fell from

( _go go go Lo—green is there_ )

and roars again. Green and smash and smash _first_ twist in his head, and he leaps onto the building, climbing _up_.

_Smash_.

( _yes_ )

XXXXXX

" _Brother!" and a hand slapping his shoulder, heavy and unaware of strength. Loki winces, forcing a smile at Thor._

" _Hello to you too, Brother."_

" _What ails you so?"_

" _Nothing, Thor."_

_Thor regards him with the seriousness that reminds Loki once more that Thor has grown up with him, knows his lies as well as Loki does on occasion. The thought is... welcome. The idea that for all his faults Thor does care, recognizes when things trouble Loki, and will likely still care after... after Loki tells him what he has discovered._

_(what Odin_ lied _about, negative in place of positive and blue)_

" _You keep your secrets then, but I am taking you somewhere. Adventure is the surest distraction to what troubles you, Loki." Thor grins again. Loki sighs, but the small smile that tugs his lips is unbidden, genuine; of course Thor would think recklessness the answer to all woes._

XXXXXX

He finds the god-thing staggering to his feet, a hand to his head, eyes wide and angry. Blue and sick twisting screech twines about him, weak and shattery and it makes him _growl_. He lunges forward.

" _Stop_!"

He slides to a halt, surprised—this is not _first_ , he has been too slow. The god-thing pants, meeting his gaze.

"I am a _god_ ," the god-thing's gaze breaks away, searching

( _now now now_ )

whatever hold there was is gone and he _roars_ , lunges forward and _smashes._

The god-thing lets out a broken sound, and goes still.

"Puny god," he grumbles, walking away.

( _Thank god_.)

XXXXXX

_Everything hurts, his chest lances fire when he moves, it is too hot, burning end of things hot, he needs cool, colder, escape_

_(break tear rend breeeeaaaaaak)_

_Until he finds dark, cool, cold, rests, shaking. Golden steps echo in the hall and he snarls and meets dream-green eyes (mother)_

_(hide.)_

_Gentle hands, not too hot hands, touch him, pull him close, he is no child, but it is safety comfort not sharp jagged edge._

" _Hush, Loki. Sleep now."_

_He can see shimmer of equation in the air, lines, integrals and derivatives, but it makes his head ache_ worse _, sharp bleeding_ wrong _, something is not_ right _what is he missing—_

_(disappeardisappear safe safe hide disappear)_

" _Dream, my son. We will see you soon. Rest," and a cool kiss pressed to his forehead._

XXXXXX

"I think Hulk just smashed Loki," Clint says over the comm; Natasha catches the slight sound of something that isn't quite glee, something bitter and angry. She'll have to ask him later.

"Right. Anyone close enough to Loki to grab the spear?" Steve asks without breaking his punch that floors another of the Chitauri.

"Bit busy," Tony replies shortly. He's dealing with a second whale in the air.

Natasha eyes an incoming set of Chitauri.

"Give me a lift," she tells Steve. He looks at her, then at the bike.

"You know what you're doing?"

She shrugs one shoulder.

"Right."

She's never fought by Steve before, but he's covered her back more than once today. He's skilled. She runs, lands on his shield, and as she jumps into the air he _pushes_ , giving her more distance, more momentum, enough that she can grab hold of the bike.

One of the Chitauri, she stabs through the spine. The other she just kicks off.

She glances over the controls, gives them a quick fiddle. She knows how to steer; that'll be good enough.

XXXXXX

_He is a child, but there is some disconnect between what he knows and the rest of him. It doesn't all fit, but the math is still there; Loki clings to it._

_Nothing else makes sense._

_Thor is there, too, but he does not seem bothered by how everything else is shifting, changing, definitions never set. Loki struggles to explain and instead finds his words deserted him. He waits. He practices, stares into the mirror, until he forgets everything except numbers that stay steady, unchanging, that make sense._

_Until he is only a child._

_He enjoys colouring, though he always follows particular sequences and sometimes the pictures he would most like to colour are not in those sequences. He likes spirals and the patterns that Mama weaves._

_He hates words, and how they do not make sense, how they grate against what he understands, how_ difficult _it is to parse them._

_He sits outside, under a tree, digging in the dirt, and catches sight of a single perfect spiral._ Shell _, he mouths to himself, trying to link word to numbers. He ties it to Thor's wrist, because golden spirals_ (shell _, he repeats in his head) belong to Thor._

_He does not know why._

XXXXXX

Natasha lands with a roll onto the balcony of Stark Tower. There is shattered glass everywhere, from where _something_ went through the window. The portal is there, already started; no one else.

The spear isn't out here.

She walks inside carefully, drawing her gun and holding it at ready. She can see movement, Loki rolled over and half crawled out of where he'd been left in the floor. The spear is not far from him.

Natasha eyes him.

(She wants to smash his face into the floor, but she restrains herself; the portal first.)

She edges closer, but he doesn't even spare her a glance, eyes closed tight, face covered in blood and cuts, arms shaking where he supports himself. Grabbing the spear, she hurries back out, grip tight.

In her hand, it _whispers_ , sounds like the voices of those who used to command her in the Velvet Room.

_Bringer_ , it sighs.

XXXXXX

_He's seventeen and prime, center of Chicago, and he smiles a perfect parabola over the party. He looks and meets_ _brown (60, 35, 23) eyes flecked with honey (233, 196, 103), feels his heart stutter stop for a moment, warmth and fire and something else._

_Only a few minutes, and the Stark that goes with those eyes is approaching, grinning._

" _Not going to use your name, then?" says Loki, studying his nails disinterestedly._

" _Sure, I can, but it's seen a bit of use. Do you want a drink?"_

" _No." He flicks a smile at this Stark. Stark's words make sense; there's no pause, no stutter grasp at meaning and he is not sure what he makes of that. What he makes of how_ sharp _Stark is, his lines and angles and his smile, perfect parabola that mirrors Loki's, vested with so many functions that he has not seen anyone else wear in a smile._

_Loki needs to be careful. To understand before he eliminates the other variables._

" _Are you sure you don't want a drink? On me?" Stark cocks an eyebrow, radiates charm as if he is the origin of it._

_Green eyes shimmer and twist infinite, then he catches Stark's gaze, leans forward; his lips brushing soft against Stark's ear, a hand slipping beneath his suit coat and teasing along his stomach._

" _That would be rather inefficient way to drink, don't you think?"_

XXXXXX

"Fury, mind telling the rest of us what's going on?" Tony says, hovering to a stop.

"The council has decided to launch a missile at Chicago. Take the whole thing down. I managed to take down one of the jets before it could launch."

The comm explodes into noise.

_Well fuck_.

"I'm on it." He launches himself towards where the jet has just launched the missile. "Jarv, kill comms."

"Yes, sir."

Things go quiet. Tony tries not to think about it, just gets himself underneath the missile and tries to figure out where to push it—catches sight of the portal that Loki's opened. The one Natasha is going to close in a few moments.

"Open a line to Natasha."

"Stark?"

"Hold the door on that portal. Gonna throw this thing at the bastards who thought it'd be a great idea to come after us."

Natasha doesn't say anything for a few moments.

"Roger that."

"Don't wait up for me, babydoll."

"Stark, I am going to rip your kidneys out when you get back."

He smiles. He likes that, the implication there is a coming back even though neither of them have any clue what's on the other side.

(And maybe, just maybe, the last of whatever the hell is in Loki's head will have broken by the time he gets back.)

XXXXXX

_Everything hurts._

_He counts, fumbles over surfaces, divides and creates math where there is none, tries to understand what is going on._

_It hurts and he is so_ cold _._

_Then a warm hand and_ _brown (60, 35, 23) flecked with honey (233, 196, 103) eyes, wet tears on T's cheeks._

What am I missing? _he asks._ What is x? _He spills what he knows, crumpled equations and numbers that are not whole._

_T tells him and Loki understands._

_His face stills._

_Oh._

_He is human, frail, and this dream has come to its end. Loki grips tight to Tony's hand, runs his fingertips across the lines in his palm, his eyes wanting to drift close, but he fights and struggles against it. He still has something to say before he lets this dream go._

" _X sub n-plus-one equals x sub n squared plus c," he tells T._ I will find you again. I will find you, I will remember this, I will remember you, you whom I understand, who understands me, whom I love. I will remember you and I will find you and I love you infinitely and more completely and complexly than I can ever express.

I promise.

_T's smile is broken, but he does not look away. His hands are so warm, so comforting, so soothing._

" _X sub n-plus-one equals x sub n squared plus c_ ," _T tells him, and Loki smiles, gratified, ecstatic, and lets his eyes slip shut._


	17. T =

_X sub n-plus-one equals x sub n squared plus c_

Every single bone feels as if it doesn't equal whole anymore but he crawls to his feet, staggers to the shattered window. Natasha ( _Bringer_ ) is there with his staff, she's going to break the portal—all according to plan, according to this elaborate function but—

_I will remember you and I will find you and I love you infinitely and more completely and complexly than I can ever express_

—everything is all _wrong_ now. Red-gold flash vanishes into the portal and his heart aches-stop-shatters because _what if they touch him_ because _what if they take him_ because _what if the portal closes before he comes back_ no no no no he only just _remembered_ this is what he lost—

Time stands still. Old and cold and dead stands at his back. He turns.

She is smiling.

Loki watches Her. He does not ( _yet_ and things _churn_ and swirl in his head, pulling) know how to divide by zero, but if he did he would destroy her so that she could not touch _him_. Distantly, he realizes he is shaking, blood slipping between his fingers, fists clenched tight to near bone-snapping and his head is buzzing buzzing buzzi—

"I have a deal for you, little prince."

He stays silent ( _raaagnaaaaaarooook_ churning gears are grinding in his head; his blood is _singing_ ).

"I won't touch him." She is close now and one too thin bone fingertip trails along his chest. "In exchange for something. I've been looking for you for such a _long_ time, little prince."

He grabs her wrist and yanks her hand away, a sneer curling his lips.

"And _what_ makes you think I want him." _Lie lie lie_.

"Perhaps you don't. Perhaps I am mistaken." She is still smiling, but she has no other expression. Her bones crack under his grip.

"What do you want." There is no desperation in his voice, all the inflection of a y = 1 line.

( _please don't take him please give him back please please please I can't go back to_ _ **loss**_ please)

( _ **anything**_ )

"Bring me worlds, little prince. Bring me _End_."

( _raaaaaaaagnaaaaaaaaaaroooook_ )

(cycles shift and grind in his head, pressure pressure pressure buzz ( _give him back_ ) the limit of L as T approaches 0 is—

"End." The world fills his mouth, familiar ( _break destroy burn_ ) weight. He stares at her and he thinks

 _Just a rather very intelligent system, fractals, sunflowers and Fibonacci sequences, ink brand that warms his heart, whole complete, I will find you, I will remember this, I will remember you, you whom I understand, who understands me, whom I love infinitely and more completely and complexly than I will ever be able to express_.

He thinks

_**anything** _

She vanishes and time lurches forward. He turns and sees red-gold gleam fall from the sky and the portal snap shut. He looks down to the tesseract and Natasha, still holding the staff.

It is easy, taking them.

( _his blood is_ singing _, bones humming and he thinks_ _ **anything**_ )

He waits for T's first breath before he vanishes. Just for a little while, just to start _this_ , just to search, to find ( _there is a book, rare and hard to find, that you will need soon to keep what you lost_ _ **safe**_ ) what he will need. He has to come back _to see_ , to touch, to make sure (to be _whole_ ) but not now, not now, right now he needs:

 _Safe_.

Make it safe, _all of it_ _ **safe**_. She will not touch him because he will bring Her End and his bones _hum_ and his blood _sings_ because he will _make it all safe_.

_T = Tony_

**Notes for the Chapter:**

> Originally, this said some stuff about Cycles, the last story in the series.
> 
> For various reasons, Cycles isn't going to happen. If you want to know why, [](http://fel-as-in-tumbld.tumblr.com/post/76033194139/this-is-the-formal-announcement-that-cycles-the>here's%20the%20formal%20post.</a>%20%0A%0AI've%20since%20updated%20the%20series%20page%20and%20first%20fic%20in%20the%20series%20to%20try%20and%20warn%20people%20that%20this%20is%20as%20far%20as%20it%20goes.%20%0A%0AThanks%20for%20reading%20if%20you%20did%20get%20this%20far%20after%20making%20it%20clear%20this%20isn't%20ever%20going%20to%20resolve%20properly.)


End file.
